What kind of repairs are you looking at? Some so called "gun docs" don't charge much, because they haven't really got a clue as to what they're doing. Some others really know their shit and charge 80 to the hour.
Shims are cheap, a KA trigger assembly can cost $35.
Guardians of Asgaard - KF32
VFC H&K 416C
VFC KAC SR16 JL Billet SBR
TM FN Five-seveN