IMHO, for a decent low-cost "clean" solid state preamp, try the AudioBuddy ($79USD at Guitar Center). For a decent low cost "clean or dirty" tube preamp, try an ART Tube MP (on sale for $59USD at musicians Friend).
There are others, but these are two I've used and have had very good results with. The retail sources I mention are just for your reference... these preamps are sold through many other retailers.