Check out garage sales, thrift stores, and (I know you already mentioned this) Craigslist! A little patience and I'm sure you can get a great deal. On Craigslist, I found a freezer for 35 that has been awesome. Since then, I've seen several more at thrift stores and on Craigslist for almost as cheap. Especially during the holiday season you'll see people getting rid of their old ones.
I would recommend getting a Magic Chef brand. They seem fit so much more for the money and footprint, from what everyone has reported. The 7.2 cf model practically calls out to become a keezer.