I don't really buy much online but then I see their list of stores in which you earn rewards / satsback includes eBay, and NameCheap.  Both of which I used in the past week or so. 

earnbitcoin

There are a bunch of stores that work internationally, but most of the of them are targeting Europeans markets (for now). You can select your country when browsing stores to see those that are available to you. 

Found the FAQ.   Doesn't say anything about geo restrictions so am assuming it is global.

https://satsback.com/faq

Also, 90 days typical between when the online order is placed and when the SatsBack are available.

It says "European".  Is it limited to just EU region?  

I don't see a FAQ.

installing the browser extension is not required to stack sats when shopping at partner merchants. You can just use the Shop now button under each store description. 