I have a shop on Etsy where I sell reusable sandwich baggies and a few vintage items. I just opened in August and have 90 sales! I have a twitter account that I use for my primary advertising, which brings in tons of item views. My average monthly bill for Etsy is about $18, which isn't too bad.
The secret to success on there is to relist items often, however it costs $.20 each time you relist an item. This brings your items back to the front page of the category and when someone searches for a word that is included in your tags. That's the other secret-- use as many words as possible to describe your items in your tags!
Here's the link to my shop if you'd like to look!
www.bellsandunicorns.etsy.com