As far as i know the audiobuddy is one of the cheapest ones you can get while still retaining useable quality.
You could get a small behringer mixing board, i think they are some of the cheapest preamps around. But probably the lowest end around, so you get what you pay for. But there are people on this board who use the preamps on the behringer boards and are totaly happy, and if you're just going for demo quality and have resonable expectations it might be worth a look. I think one of the major complaints about the behringer boards (aside from low quality preamps/components) is the quality control is unbelievable. It's more common than not that you're first board will have problems, and your second, and your third, etc... People get them with the power supply missing, the burst into fire, LED's don't work, channels go dead, etc...
i think you can get a small behringer board with 4 preamps in it for dirt cheap. You might not use the rest of the board but if you break down the price per channel of preamps it's pretty damn cheap even if you don't use the board. Hell even a Mackie 1202 is pretty cheap if you think of how much preamps of that quality would cost as standalone units.
now I want to know is there any other mic preamp that may be a little bit cheaper? It doesnt have to sound like professional quality I am just looking to record some demo cds.