I googled "epubs" to see what stores came up and found
http://www.booksamillion.com/ - a store I had basically forgotten about since their brick-and-mortar store in my area closed a few years ago. I compared prices of several books on Books A Million and Kobo and BAM's prices were lower, so I bought a couple. I am in the US - I don't know if they sell to any other countries.
Note re: purchase experience - when I first finished checking out and went to Downloads to download my purchases, it said "order in process", but after I clicked out of that page and then went back to it my books were available for download.