What is a good clean site to host images on, that you can link to through another website?

By clean, I mean relatively devoid of banners, ads, and other miscellaneous junk that could color the moods of the sale. If a pastor is looking to buy my vehicle I don't want an ad for "late night hookups" on the sidebar.

I'm going to re-list my truck on Craigslist but I hate their photo limit. You're held to four tiny photos that do little to tell the story of your vehicle. I'd like to take ~20 highly detailed photos and simply link them into the Craigslist ad. Need to get this puppy sold... this soft market is kicking my tail.

I have a photobucket account but I want something more professional to link to. Oh, and cheap is the key word. Free is even better.

Suggestions?