Are you sure its actually a head gasket and not a lower intake gasket? I found those can go pretty easy if the engine gets hot. The cost between a Gen1 and a Gen2 head gasket can be pretty significant depending on what engine, is that a DOHC 3.5? Also, are they going to send the heads out for machining? It all depends on the amount of work your getting done. I know a basic head job with no machining can be in the 400 range

Richard E
1989 Montero - Stock-ish
1989 V6 Auto Raider - 5.3 Vortech Swap.
1987 Mitsubishi Starion 2.6t, soon to be 3.5
1983 Honda XL600R