Auto Repair cost on 1996 plymouth voyager?

I have a 1996 voyager and we had it towed to a shop. The guy is friends with someone I know as well. I received a call about it and was told that the Alternator, Timing belt and Water pump had to be replaced. He quoted me 625$-650$. Now...is that a fair value for the repair and parts. He said that he has a used alternator as well. Thank you in advance for your answers