The easiest pitch would be to have a base retainer (say 1000$ a month) and then % of revenue increase since the baseline.

It makes it easy for them and is far compelling cause you are now a revenue cost rather than a recurring sunk cost.

The typical ecomm transaction has 10-12% margins? And then CAC etc has to be amortized. So you'll either have to pitch fora tiny sliver of topline or a % of profits - as that also aligns outcomes where the consultant just doesnt run promotions giving away all the margins and think short term.

Given this math, id say 10K a month revenue seems a bit early. Might want to look at ecomm stores that are a bit further along the way, or use pre-recorded content on subscription to tackle this early market (as it potentially) can become your funnel.

From what I've seen from other email consultants, typical rates can range anywhere from $50-$200 an hour which all depends on your experience, where you're located (for example if you're in NYC you can probably charge more than if you're in Savannah, Georgia), and what you can offer. If you're just starting out and need to build up your client base and have no references, I would definitely recommend starting on the lower end and offer your clients the ability to cancel any time with 7-30 days notice if they're not happy with the service. That way you reduce their risk and increase your chances of having them run a test with you.