When I put my bike on the repair stand and turn the pedal, is the rear wheel supposed to spin freely I recently bought a cheap road bike.  I feel a little drag in the back. When I put it on a repair stand and turn the pedal,  the wheel spins a few times and stops.
Could be as simple as the wheel rubbing on the brakes - rotate the pedals and listen for a scraping noise as the wheel contacts the pads. If this is the case, check that the wheel is true by observing for any wobble side to side as the wheel rotates. If that looks ok your brakes probably need adjusted away from the rims. 

Start here for brake adjustment http://sheldonbrown.com/canti-direct.html#about but it very much depends on your particular brake type. 

Wheel truing info can be found here - http://www.bikeradar.com/gear/article/workshop-truing-a-pair-of-wheels-19199/