How the sales objective works
You choose sales at campaign level, then say inside the ad set where the purchase happens: your website, an app, a shop on Facebook or Instagram, or a messaging conversation. The performance goal decides what delivery chases — the largest number of conversions, or the largest total value of them — and a catalogue can be attached so that ads show the specific products a person has looked at.
None of that functions without a purchase event reaching Meta with a value and a currency attached. That event comes from the pixel in the browser, from the Conversions API on your server, or ideally both, matched together so the same sale is not counted twice. The objective is only as trustworthy as that one event.
Why the sales objective matters
It is the only Meta objective that connects spending directly to money. Every other outcome — reach, clicks, enquiries — is a proxy that somebody later has to argue is worth something. Here the argument is settled by the till.
It also changes who the ads find. Told to maximise conversions, delivery looks for people likely to buy anything. Told to maximise value, it looks for people likely to spend more, which is a different and usually smaller audience, and the cost per purchase rises even when the campaign is doing better business. Knowing which of the two you asked for explains most confused conversations about a rising cost per sale.
Common mistakes with the sales objective
The first is optimising for a purchase that hardly ever happens. Delivery needs a reasonable flow of the event it is chasing before it can find a pattern; with sparse purchases it never leaves guesswork, and the budget is spent learning nothing.
The second is double counting. When the pixel and the Conversions API both report a sale without a shared event identifier, reported revenue inflates and return on ad spend looks better than the bank account does. The third is treating an order as revenue. Where cash on delivery is normal, as it is across much of Nepal, a placed order is a promise: some are refused at the door, some are never paid for, and a campaign optimised on placed orders will happily find more of exactly the customers who do that.
How to act on it
Start in Events Manager and confirm the purchase event fires once, carries the correct value and currency, and matches what your shop platform recorded. Give browser and server events a shared identifier so they deduplicate properly. Until that is true, no report from this objective is worth acting on.
If purchases are too infrequent to optimise on, optimise for the step before — add to cart or checkout started — while still reporting purchases as your measure of success. Reconcile Meta’s revenue against your own accounts on a regular cycle rather than trusting the platform’s figure, and where cash on delivery applies, send back the delivered and paid order rather than the placed one. That is the difference between ecommerce advertising that grows a business and one that grows a returns pile.