Hi there - I think Shopify *could* work for you but only if you invested a fair amount of time (and money) in things like blogging, SEO, online ads etc. to build an audience for your products. The advantage of online marketplaces like eBay is that the audience is already there (although there is still work to be done to reach it). And as I think you’re alluding to, Shopify is probably better for selling the same products over and over, rather than one-offs. But that said it can still work for that too, especially if you’re doing content marketing well.