How much should you budget for Facebook and Instagram ads?

Start with the contribution from one order

Subtract procurement or production, packaging, payment fees and the portion of delivery you pay from the revenue you retain on an order. Include expected cancellation and return costs. The remainder must cover advertising, fixed costs and profit. If you start with a VAT-inclusive price, first convert it to revenue excluding VAT and use a consistent basis for all costs.

Illustrative example, not a client result: an order produces RSD 6,000 in net revenue and leaves RSD 2,400 after variable costs. If you want RSD 1,200 left after advertising for fixed costs and profit, your planned maximum cost per acquisition, or CPA, is RSD 1,200. A purchase costing RSD 2,000 to acquire may look acceptable in an ad account while still being too expensive for that objective.

For services, start with the cost of a qualified enquiry and the percentage of those enquiries that become clients. If only one in ten becomes a customer, RSD 500 per enquiry means RSD 5,000 in advertising per customer. Measure that conversion rate rather than treating the example as a universal assumption.

Turn the business objective into a test budget

Example plan: ten purchases at a target CPA of RSD 1,200 imply RSD 12,000 in planned spending. Spread across 14 days, that is approximately RSD 857 per day. This is a calculation scenario, not a forecast that the platform will deliver ten purchases. Actual CPA may be higher, and the test may finish without enough data.

Ten purchases are neither reliable proof of stable profitability nor a universal statistical minimum. This plan simply defines the scope of the attempt. Comparing similar ads or seasonal changes may require substantially more data.

Separate media spending from creative production, measurement setup, page development and campaign management. If you have EUR 300 in total, you cannot treat all EUR 300 as both your ad delivery budget and the total project cost.

What should you test with a limited budget?

Start with one clear offer and a small number of distinct creative ideas. A different message or product demonstration provides a more useful signal than several almost identical banners. Avoid splitting a small budget across so many audiences and campaigns that none receives meaningful spending.

Before launching, write down your hypothesis: who the offer is for, why they would buy and what would indicate that the message works. For example, a demonstration video should bring relevant visitors to a product page that clearly explains dimensions, pricing and delivery.

Set a spending limit and decision criteria in advance. If visits arrive but there are no additions to cart, review the offer and page. If carts exist but purchases do not, check delivery, payment options and checkout itself. A low purchase count alone does not tell you which part of the system is weak.

When should you increase the budget?

An increase makes sense when sales data is reliable, orders are actually fulfilled and contribution after advertising remains acceptable. Check inventory, delivery speed and support capacity too. More spending cannot fix an unavailable product or a process in which enquiries go unanswered.

Do not judge a campaign on one good day. Compare several days and allow time for cancellations and delayed event reporting to become clear. Use the same reporting period and distinguish new customers from existing customers.

Checklist

• Order contribution and target CPA calculated.
• Media spending separated from other costs.
• Purchase flow, confirmation page and order processing checked.
• Test hypothesis, spending limit and decision date defined.

Is a small budget pointless?

No, provided the objective is narrowly defined and the cost is acceptable. A small test can reveal a messaging or sales-page problem, but it may not generate enough purchases to draw a reliable conclusion about future earnings.