I use
http://www.storenvy.com for selling custom vinyl toys, painted minis, and art. If you just use basic functionality and decline being included in their Marketplace, it's totally free (minus your usual PayPal fees.) Easy to set up, you can track stock, print invoices, and get use of simple discount codes. If you sell via the Marketplace, they take a percentage, and if you want add-ons (more discount codes, marketing tools, etc.) you pay a fee.
Depending on your technology comfort level, you can also set up sales buttons right in PayPal, then copy & paste the code right into a web site, blog, etc. (Speaking of which, there are a few options for cheap & easy sites/blogs, if you're interested.