Check out Newegg.com and I know for a fact that the other day when I went to Radioshack they had a huge sale going you could get an HD Vivitar for $150. They also carry a brand called Dxg or Dgx and it's pretty cheap but it comes in 1080. Newegg may be a little cheaper.
Check Amazon too. I'm on there right now and they have some awesome deals on new and used gear.
If you want full 1080p, you arent going to get anything decent for cheap. I suggest either the Panasonic HDC-SD60 which is £400 so about $600. Or the Sony Handycam HDR-CX116E which is £450 so about $660.
Sk8r is correct. the Kodak and Flips are not a true, crisp, 1080p quality. I have talked to a lot of FLIP owners and they were very disappointed when playing back video on TV screen saying the footage was grainy. It looked pretty good when watching it back on the little screen on the FLIP but not on anything else. Most of them said they returned them and then moved on to the Kodak.
These are great for small portable, every day filming, uploading to youtube, but NOT for transferring over to DVD or showing footage on Widescreen TV's.
You do get what you pay for. If I was just doing small things for my own personal enjoyment..then the Kodak or Flip is great. If you are going to be editing it on your computer and making promotional quality DVDs....you are better off spending the $600 on a much better HD camera.
You have to weigh all the pros and cons and see what you are willing to sacrifice for price.
When I posed nearly the same question to a filmmaker friend, he suggested the Canon HV30 (there's a 31 now, I believe). It'll run around $500-$700, depending on where you find it. But it's good enough to shoot a feature film, according to my friend. And really, considering he's shot a feature film, I trust his opinion.
I recently bought a Canon Powershot SD780, which takes 720p video that looks fantastic, it also takes it in .mov so it's pretty easy to work with. It's primarily a photo camera, but it's a better all around value than the flip IMHO, and in my experience is a better camcorder than the flip as well. I got a refurbished one on ebay (practically brand new) with a case, tripod, 8gb memory card, sd reader and a couple other things for under $170 here.