1995 Corolla Wipers

Here's my situation. I know very little about wipers. I took my girlfriends 95 corrola into a mechanic because the wipers were 'popping off' every couple months and we kept having to take the car in to get them put back on. The mechanic said that this is going to keep happening unless we have them fix it---

He invoiced me 500$ for parts stating that the wiper transmission, linkage, assembly, everything needed to be replaced. Somehow I doubt all of those things cost 500$... can anyone suggest what I should do? :disappoin

Thanks a lot,
Bob