I have just installed the premium script of Bigup online store and will soon populate it materials I am looking forward to include over 100 titles here that cover a lot of interest only problem ie I need help on Bigup payment where buyer can easily download the materials after paying Bigup coins..
We will dedicate a thread in the BigUp Forum to this subject but as a quick start you may want to take a look at C-CEX and their merchant documentation:
https://c-cex.com/?id=merch
Eventually there will be more options for merchants but the C-CEX option is a good one that is available right away