I've seen several people use tindie.com :
https://www.tindie.com/ I don't know if it's the best, the fees etc.
Anyway.. a domain name is 10-12$, a shared hosting account is a few dollars a month, people can pay you using paypal , or you could just point people to your ebay account (costs something like 50 cents to put a product with buy it now for a month and some 5-10% fees on each sale)
I wouldn't bother with distributors or stores ( like adafruit or sparkfun or something like that) for such a cheap product.. they'll most likely want at least 25-40% of the value added as their profit, and a minimum quantity to ship to them etc etc etc...