Man...unless you are a glutton for punishment you might want to turn and run on that one. Unless you have a doner bike...spokes are rusted which means cleaning the wheels up is not going to happen so you will need new wheels. Powdercoating it new around $100.00. New cables, probably tubes/tires, and all the cleaning you are going to have to do to components....$75-80. (Gallon of Simple green =$12.00)

Craigslist can do you better than that. Just wait and be patient. I might offer him $40.00 just to save the frame and crankset, handlebars. Then take my time fixing it up. NO WAY $100.00 though. I can find bikes in way better condition for less work...you can too!