There is a Cambridge Audio C500 that someone is selling here for $155 including the optional remote control which cost $50 by itself. The C500 is one of the nicest sounding super low cost preamps I've heard, that is modern in features like a remote control, etc.
If you can find an old Superfon preamp, it would do nicely also.
If you can find an old Superfon preamp, it would do nicely also.