Edit: Okay, I'm an idiot. You have to replace a freezer in order to get the rebate. I guess there would be ways to "replace" a freezer you don't actually own, but I don't advocate fraud.
I know most of us absolutely HATE taking money from the gub'mint, but I'm thinking that this might be too good of a deal to pass up:
Energy Efficient Appliance Rebate Program.
Then I found this chest freezer on Sears.com:
Kenmore 13cu. ft. Chest Freezer for $359...
359
-180
=179 Half Price!
You have to register for the rebates by a certain date, but it looks like it could be a pretty good way to save a ton of money on a lagering freezer.