What kind of game are you thinking of buying? EM, SS, 1990's Wiliams, new Stern? If you buy a newer Stern, you really shouldn't have to much repair.

Like others have said, sometimes it is more fun tinkering and fixing up a dusty old game and making it shine.

If you haven't already, read these web sites carefully and buy a soldering iron and voltmeter. Don't be scared, as long as you have patience it is not bad. It is not rocket science. Patience is really what it takes more than anything else. Some people have patience and some just don't.

http://www.pinwiki.com/wiki/
http://www.pinrepair.com

Take a look at the game specific parts on Marco to get an idea of parts needed for your game:
http://www.marcospecialties.com

These sites will tell you just about all you need to know to get a good start.

It is much easier to fix your own games than trying to track someone down.