Buttons!

Okay, so I finally figured out the first thing I wanna sell to build my brand. Buttons! But the thing is I don't know on what platform I should sell them. I've had an Etsy before but it was super casual and I only sold a few things. Plus it seemed confusing at the time with the stipend that they take once you get to a certain point. My friend told me Instagram was a good place but I don't know what that would look like. Would people just DM me when they wanted to buy something? How would I make a receipt? if anyone has any ideas or tips let me know.