There are some amazing online shops. I currently have a few myself.
I think etsy is a great one. I also love rubylane.
My favorite online jewelry shop is called 1st dibbs. Though the jewelry is exquisite, they are ridiculously expensive…if you have the means I would highly recommend checking it out.
I do not recommend ebay. I once had a shop that did very well, but they changed their policies and there are a lot of knockoffs and people have really been taken advantage of.
I also have a jewelry/business page on Instagram. My customers seem to like that the best because there is no tax as well as astronomical fees.
Check some of these shops out and get some good inventory together and you could actually do very well for yourself.
Good luck! 
