$40 at my shop (in west oakland) gets you a basic tune-up, which includes minor wheel truing, drivetrain adjustment (derailleurs and whatnot), a clean chain, brake adjustment, hub adjustment, and the bolts tightened up. anything that needs to be replaced gets replaced for whatever the parts cost, no extra labor.

$80 gets a "performance" tune-up, which is pretty much everything above, plus cranks, cassette, derailleurs and taken off, disassembled and thoroughly cleand and lubed, plus major wheel truing.

$120 is basically where we take the bike totally apart, clean it, repack bearings, and re-assemble everything.