First up is this 1988 BMW M5 E28 project offered for $13,500 in Fremont, CA via craigslist. The seller says that the interior is perfect, but it has been in storage for 5+ years and that it needs paint and a fuel pump or relay. However, if the S38 inline-6 rated at 256 horsepower from the factory is in good shape this could be good deal because prices of these things have shot up recently and BMW only built 2,191.
Next is a 1991 BMW M5 E34 offered for $9,200 in San Jose, CA via craigslist. This white beast features all original paint (Apline White II) and has been a California car since new. It does have 242,000 miles on the odometer, but the S38 inline-6 rated at 307 horsepower will be reliable if properly maintained. The E34 M5 has also shot up in price over the past year (or two) but with 12,254 produced you (and other buyers) have more options to chose from.
Finally we have this 2001 BMW M5 E39 offered for $8,500 in San Mateo, CA via craigslist. This M5 has a few miles on the odo (218,232) but the seller claims it runs/drives great with no error messages or leaks whatsoever. The seller has put in new tensioners, belts, alternator, & vacuum hose on the S62 V8 rated at 394 horsepower. With 20,482 produced the E39 should be reasonably priced for a few years to come.
See a better deal on a used M5? firstname.lastname@example.org