It's not the cost of the tub -- it's all the molding and tile around it. What a chore.
My best friend refinished tubs for about a year in Seattle. The chemicals were so dangerous to the operator he soon quit. But he said after the vapors were gone, it looked brand new for a lot less hassle than ripping it out and replacing it. Now he lives in Texas and drills wells. He's got a penchant for unusual vocations.