If you get the cheapest thing you can find i wouldnt expect it to sound all that spectacular to be honest...

If course you could buy a passive preamp which is more like just volume pots but thats a different matter.

For cheap id reccomend the Bottlehead Foreplay, you can build one for around 200 bucks and best part is that its tubes It is a rather good sounding peice

Haoleb's Audio/DIY Website