As you probably know, tires and tubes will run ~$50-70 if you install them yourself. If you have a bike shop do the tune up, probably another $50 - 70 to replace brake and derailleur cabling, and brake pads. It's not hard to get $200 worth of use out of a bike if you're buying it to ride, but you won't make that back if you ever sell it.
__________________
"I had a great ride this morning, except for that part about winding up at work."
Bikes so far: 2011 Felt Z85,
80's Raleigh Sovereign (USA),
91 Bianchi Peregrine,
91 Austro-Daimler Pathfinder,
90's Trek 730 Multitrack, STOLEN:
80 Schwinn Voyageur (Japan)