Building a retail media budget in which every amount can be traced to a document

Retail media costs and pricing need a defined buyer, service and billing event before a budget can mean much. An England retailer funding its advertising infrastructure has a different cost account from an advertiser purchasing that retailer's inventory. Keep both accounts visible where necessary, but do not combine their spending and revenue into an unexplained return figure.

This guide covers retailer or marketplace controlled advertising inventory and associated data operations. Research on 6 September 2026 did not obtain current, comparable quotations with complete England scope and VAT terms. Price, rate and volume inputs therefore remain UNKNOWN. The method below contains no invented market benchmark, budget or achieved return.

State whose budget is being prepared

Write the decision at the top of the model. For the retailer, it might concern the cost of operating a specified on-site advertising service. For the advertiser, it might concern spending on an agreed placement within that service. These are examples of modelling questions, not accounts from real businesses.

Assign each cost to the party that incurs it. Distinguish money received by the retailer from working media paid by an advertiser and fees paid to a technology supplier. If a commercial arrangement changes the flow, map the actual invoices before constructing totals.

Describe the retailer property, format and service period. State whether campaign management, implementation, measurement or audience processing is included. A figure covering only media delivery should not be used to describe the cost of building and operating an advertising programme.

Keep general merchandising, product inventory costs and unrelated media channels outside this model unless they are deliberately included in a stated incremental-contribution calculation. A budget that changes its boundary between alternatives cannot establish which option costs less.

Make the evidence record precede the amount

For each proposed entry, record the direct official price source or signed quotation, its date and validity period. Capture the currency, quantity unit, billable event, service term, geographical scope and VAT position. Keep any missing field marked UNKNOWN rather than borrowing a term from another supplier's page.

Criteo's View Your Fees record, inspected on 6 September 2026, describes account-specific fees expressed against working media spend. It distinguishes platform and professional-services categories. This supports asking for an account-specific breakdown; it supplies no universal fee rate for an England retailer or advertiser.

A public description of a charging method is evidence about that method, not the value of a negotiated quote. Separate list prices, account settings and invoiced amounts if those records later become available. Preserve the original document so a revised offer does not overwrite the basis of an earlier decision.

Use an evidence status beside every input: quotation, invoice, measured quantity or projection. This is a proposed editorial convention for a reproducible workbook. A projection should never acquire the status of an observed quantity merely because it has been entered into a formula.

Define the events that quantities count

The IAB/MRC retail media measurement guidelines, published in January 2024, distinguish media delivery and sales measurement concepts. Use the source as industry methodology, not UK law or a tariff. Confirm the exact specification adopted by the parties.

Quantity	Meaning to establish before costing
Ad requests	Calls asking the advertising system for a decision
Served impressions	Delivery events counted under the agreed serving definition
Viewable impressions	Impressions meeting the applicable viewability measurement criteria
Clicks	Recorded interactions passing the agreed counting and filtering rules
Attributed sales	Sales credited under a stated attribution method and window
Incremental sales	Estimated sales caused by advertising relative to a counterfactual

These quantities must not be silently substituted for each other. Obtain the event definition from the measurement specification and the billable definition from the contract. Where they differ, preserve both and explain the reconciliation rather than renaming one to match the invoice.

For example, a system may receive a request without a corresponding displayed unit. Treat that as an implementation question to inspect, not an assumed ratio. No fill rate, viewability rate, click rate or conversion rate has been supplied for this model.

Keep the quotation table blank until it is usable

The following is a recording structure, not a set of supplier offers. All proposed monetary entries are in GBP once evidence supports that currency; source currencies must also be retained where different.

Cost line	Amount or rate	Unit and term	VAT treatment
Agreed implementation scope	UNKNOWN	UNKNOWN	UNKNOWN
Recurring service	UNKNOWN	UNKNOWN	UNKNOWN
Usage-based charge	UNKNOWN	UNKNOWN	UNKNOWN
Campaign operations	UNKNOWN	UNKNOWN	UNKNOWN
Measurement or assurance work	UNKNOWN	UNKNOWN	UNKNOWN

Add the payer, supplier, evidence date and document location to each completed row. Do not give a possible cost line a positive amount until an authorised estimate or commercial record exists. UNKNOWN is a missing-input state, not a substitute for a nil charge.

Record credits and rebates separately from the charge they affect. Ask whether they are unconditional, earned only after a commitment or contingent on later reconciliation. This is a proposed quotation check, not a statement that any named provider offers those terms.

Use formulas that preserve the contract boundary

For a charge defined per event, calculate the line amount as documented rate multiplied by the eligible event quantity. If a rate is quoted per bundle, first divide the quantity by the documented bundle size. Use the agreed rounding and minimum-charge rules rather than an assumed convention.

A spend-linked fee uses its own basis: verified eligible spend multiplied by the documented fee fraction. Check whether that basis includes other fees, taxes or credits. Do not apply the percentage to a wider total simply because the model already contains it.

A fixed charge belongs to its contracted service period. Converting it to a shorter planning interval requires a stated allocation, which is not necessarily the amount invoiced. Keep cash timing separate from the management allocation so the budget does not imply payment dates the contract never promised.

Calculate a known subtotal only from validated rows, and label it partial if any required row remains UNKNOWN. A complete total cannot be reported while necessary inputs are missing. The model should explain which document or operational estimate would resolve each gap.

Deal with VAT as a reviewed input

HMRC's VAT Notice 700 explains input tax and the conditions affecting recovery. Do not assume that VAT shown on an advertising invoice is fully recoverable for every buyer. Keep invoiced VAT, recoverable VAT and irrecoverable VAT separately identified by the finance reviewer.

For services involving overseas suppliers, VAT Notice 741A covers place-of-supply rules. An England operating location alone does not settle the tax treatment of each service. Ask the accountant to examine the actual parties and supply before assigning a rate or reverse-charge treatment.

No tax rate or recovery fraction is assumed here. Preserve VAT uncertainty in the blank model, including its effect on cash needs and economic cost. This guide is general budgeting information, not tax or legal advice; qualified UK review must assess the actual transaction.

Budget the work needed to produce trustworthy data

The ICO's advertising guidance requires consent for storage and access technologies used for online advertising. Ask the implementation owner to identify the proposed work needed for the relevant permission handling. The existence of that requirement does not establish a supplier charge or a standard implementation cost.

Security review also needs a defined scope. The NCSC cloud supply-chain principle addresses dependencies and access within a provider's supply chain. Any internal assessment effort or external assurance service should be costed from the actual plan, with an owner and evidence for the estimate.

Treat these as possible work packages to investigate, not mandatory purchases of a named product. Some tasks may be covered within an existing agreement; others may require additional work. Until the responsibility and terms are established, the amount remains UNKNOWN rather than an invented contingency percentage.

Separate reporting from causal return

Recorded sales show what the transaction system captured. Attribution allocates credit according to a defined rule. Neither alone establishes how many sales would have occurred without the advertising. Keep the data source, attribution method and causal evaluation in different sections of the decision paper.

HM Treasury's Magenta Book analytical methods explain counterfactual approaches to evaluation. This is UK government evaluation guidance used for methodological context, not a rule requiring private retailers to use a particular design or a claim that a retail campaign has been evaluated.

For the proposed commercial model, define incremental contribution before campaign costs as G and the incremental campaign costs within the same scope as C. The net-return ratio is then (G minus C) divided by C. This is an explicitly defined modelling convention, not a measured ROI result.

G must already reflect the relevant product economics, returns and other agreed contribution adjustments, while excluding the campaign costs counted in C. Otherwise the calculation may mix sales with profit or deduct the same cost twice. If G is unsupported, C is incomplete or the denominator is not positive, the return stays UNKNOWN.

Stress the assumptions without fabricating a forecast

Create alternative scenarios only from documented input ranges or clearly authorised assumptions. Vary the uncertain input while keeping scope and accounting treatment fixed. Record who supplied each assumption and why it is being used. Do not populate a low, central and high case with arbitrary volumes.

Show what changes the decision: a different service boundary, a contractual minimum or an uncertain incremental contribution. Avoid presenting the resulting scenario as a forecast unless a forecasting method supports it. A budget can remain useful while admitting that the likely commercial outcome is not yet established.

Finish with an unresolved-input register and a decision date. Request the missing quotation, tax review or measurement plan before committing to a complete cost or return claim. Before publication, assign real authors and qualified reviewers, refresh every direct source and retain the publication hold until those checks are complete.