The best places to sell ACEO art online are eBay.com and Etsy.com. On eBay, start with low prices. See if you can attract any bids on your ACEO art. If you aren’t successful at first, you may need to lower your prices. I suggest starting on eBay before trying Etsy. Although you may get a higher price for your ACEO pieces on Etsy, it’s more difficult to make sales there.