What are you looking for it to do? A dashboard gauge is one thing, a data logger is another.
Myself, I've got the LM1 system from Innovate, with the tailpipe adapter. That way I can use it on any vehicle, read the display while I drive if I wish, and datalog what was going on.
If you're really interested in low buck and kits, there was a good thread on the GRMS board about a 9 months ago. You can get kits for a dashboard type display for under $100.