20 Jul Boost ROAS Without Reducing Cost Per Purchase: The AOV Lever
Reducing cost per purchase isn’t the only way to improve ROAS. Increasing average order value (AOV) — how much each customer spends per transaction — moves ROAS just as directly, without touching acquisition cost at all. One client went from roughly 5x ROAS to 7-8x purely by increasing basket size, with cost per purchase essentially unchanged.
The case: a threshold voucher
The mechanism was simple: offer a discount tied to a spend threshold rather than a flat discount — for example, $10 off when a customer spends $100. Customers who would normally spend $50-60 had a real incentive to add more to their basket specifically to unlock the discount. The result was a meaningfully larger average order, even after accounting for the discount given.
This didn’t change how much it cost to acquire each customer. It changed how much each acquired customer was actually worth — which is exactly why ROAS moved so directly.
Why this is a genuinely separate lever from cost per purchase
It’s easy to treat “improve ROAS” and “reduce cost per purchase” as the same problem, but they’re not. Cost per purchase is about spending less to get the same result. AOV is about making each result worth more. A campaign with a completely unchanged cost per purchase can still see a significant ROAS improvement if the average transaction value goes up.
This matters because it opens up an entirely different set of levers beyond ad creative, targeting, and bidding — things that live on the store and offer side of the business rather than in Ads Manager at all.
Other ways to apply this
The threshold voucher is one specific tactic, but the underlying lever — increasing basket size — can be pursued several ways:
- Spend-threshold discounts, as in the case above, rewarding a bigger basket rather than any single purchase
- Bundling complementary products together at a combined price that encourages buying more than one item
- Free shipping thresholds, which push customers who are close to the line to add one more item rather than pay for shipping
- Post-purchase upsells at checkout, capturing additional basket value from someone who’s already decided to buy
None of these require touching the ad account. They’re store and offer-side decisions that directly influence what your existing traffic is worth.
Why this is worth thinking about alongside cost per purchase
If a business has already put real effort into ad creative, targeting, and bidding, and cost per purchase has plateaued, that doesn’t mean ROAS has to plateau with it. AOV is often an underused lever precisely because it doesn’t feel like an “ads” problem — but it moves the same output metric just as effectively.
This breakdown is written by Jason Gan, a Meta Certified Professional and Badged Meta Business Partner who has personally audited over 1,000 advertiser accounts since 2010. You can see real account breakdowns on the Jason Gan YouTube channel.
Frequently Asked Questions
Can I improve ROAS without lowering my cost per purchase? Yes. Increasing average order value (AOV) improves ROAS by making each purchase worth more, without needing to change the cost per purchase at all. A higher-value basket at the same acquisition cost directly improves the return on the same ad spend.
How can a discount threshold increase average order value? A spend-threshold voucher (for example, $10 off when you spend $100) gives customers who would normally spend less an incentive to add more to their basket to unlock the discount. Even accounting for the discount given, the larger basket size can meaningfully increase overall order value.
Is increasing AOV better than reducing cost per purchase? Neither is inherently better — they’re separate, complementary levers. Reducing cost per purchase means paying less to get the same result. Increasing AOV means each result is worth more. A strong ecommerce strategy usually looks at both rather than treating cost per purchase as the only variable that matters.
If you want to know which lever has more room to move for your account
Book a Meta Ads Audit — $80 / 30 Minutes →
No login required. Just a screen share, your real numbers, and a clear read on whether cost per purchase, AOV, or both are worth focusing on.