I think the best thing you can sell with your online shops are video games because gamers are always on the bitcoin you know and that is nice because games are expensive and that means
that you will earn allot of money off course.
This is in demand item online, especially when you are using steam's game then you could start up an online business and sell steams game cheaper. I know you can have some partnership deal with steam, since they are now accepting bitcoin that is going to be an advantage for you. You can just sell it wherever you want easily, for example in social medias.