Hi! I don't know about creating a site from scratch, BUT depending on the number of different items you have (if you have 5 or under) I can recommend Bigcartel's free version (I think it's called basic gold package)
It is limited though - only 5 item listings and only 1 picture for each listing, and you have to send out emails (customer service such as 'item shipped' emails) etc. on your own.
Though, there are some work arounds. For example; if you have 5 different keychains you can put a picture of them all as 'one item', and just write in the description that buyers need to specify which one they're buying, in the comment section
I hope any of this helps (and that someone who knows more about setting up own shops shows up!) (◍ ´꒳` ◍)b