Started out with Vendio. Really expensive and when I called to ask why my bill went from $20 (150mb) to something like $40 and they charged me $7/ea for every call to Tech Support. Vendio is owned by eBay and treats their customers even worse than Ebay does.
Signed up at Image Viper. Inexpensive but they have this Rate This Picture insert on all photos which makes listings links look cheesy.
Signed up at inkFrog. Long on promises, short on delivering. Advertise $9.95 a month/monthly billing through Paypal. Didn't work (I think they make sure it doesn't work because they know people will bail out once they find out how badly they suck). Greg Sisung (President) said bi"Strange, I noticed PayPal has been doing this lately. Have you tried contacting them to see if they can get it setup for you? Do you have another browser you can try maybe (or another computer?) - i wonder if it's a browser issue."/i/b I called Paypal they said it was a Inkfrog issue. When I emailed Greg again he said bi"...unfortunately we have no contacts with PayPal to get any of this stuff resolved :-("/i/bThis is NOT THE CASE AT ALL. Anyone with an account can call Paypal Support for free. I even provided him with Merchant Account (and regular account) contact information. So I ended up having to sign up for 3 months. BIG MISTAKE. Their Tech Support is pretty much non-existant and once you sign up they string you along with excuses. Their uploader doesn't work and software is Apha or at best Beta. Don't fall for their hype.
Finally signed up at Seller Source Book. They seem to be the best. Not perfect but close enough. I will be using a combo of Image Viper and Seller Source Book. It's still cheaper paying for both than using Vendio. I'll cancel Inkfrog shortly.