I love ArtFire. Of all the online venues where I have a presence, ArtFire is my favorite - hands down. Here's why, in no particular order:
1) Cost: There's a fixed monthly rate. No listing fees, no fees when items sell. No hidden, unexpected costs. This makes it very easy to budget.
2) Knowledge Base: The forum, the Help Guides, the Inside Handmade podcasts -- all excellent. The education I'm receiving about search engine optimization (SEO) and social media (loved the Social Media Bootcamp series) alone is worth the cost.
3) The "Admin": The folks who run ArtFire actively participate in the forum discussions. Getting a straight answer couldn't be easier.
4) Selling: People have found my items via Google and purchased them. While shoppers are welcome to sign up to join the ArtFire community, they are not required to do so in order to purchase.
5) Really cool stuff: Okay, I've been writing from the perspective of a seller, but let's face it: I'm a shopper too. ArtFire features some of the most amazing handcrafted items, vintage items, and crafting/art supplies.