Question

What metrics do you use when optimizing low budget e-commerce stores?  

Answer 1

ROAS and ROI, but if you aren't running high enough budget to consistently be getting conversions, use link click CTR and link click CPC

Answer 2

Highest performing ad group as measured by highest conversion rate

Answer 3

The same ones I use with high budget ones

Answer 4

Leading indicators like cost per add to cart/checkout initiated.  

Answer 5

Scrap the shit above they have no idea how to run small shops. Low budget e-commerce stores = no conversion data to optimize. Do this instead focus on LOW CPC and HIGH CTR. Make your audiences as niche as possible (no more than 100. 000 total reach) and focus on getting 3%+ on CTR and as low as possible CPC. This way you generate traffic that you can later remarket toy with an offer. Focus on your copy and your audience. If you achieve the above results but still you have no conversions then you should go and fix Conversion Killers on your website (low loading speed, bad creatives, really difficult navigations, or bad UX on the Checkout process).