But those are the cheap ones. Keg prices have been steadily on the rise. I picked up some ding and dents for twenty bills shipped five years ago. They serve their intended purpose of dispensing beer happily. You are going to pay pretty good coin for the blemish free ones unfortunately these days.
Check out the "loose handle" ones. Definitely worth the price. Most are still secure, and might just need a dab of Gorilla Glue to make them perfect. I highly recommend them. They sell new ones for a decent price too, but I hear they need a good scrubbing to get the oils off of them from the factory...
if you want real cheap craigslist is the way to go but that's always a crapshoot. Just have to keep checking and jump on what you find. Most used kegs will run you $50-$60 if you buy them from a website. Sometimes homebrewing.org has deals like 3 for $120 or whatever. I'd rather pay a little more and know I can return it other buying from some random person online.
Just have to be in the right place at the right time it seems to get a good deal.