3.8 toast Waterpump ?

So its my girls car so i wasnt driving it. She and her father over heated it really bad, no water, about three times. The whole pinging, knocking, bit. So it needs a new motor. She doesnt want to spend much, of coarse. So her dad decided to go with a place in the valley called UnitedMOTORs. (Anybody used them before?) 1200 for a new long block. Looking for new parts, Ie water pump, power steering etc. I say GM pump, and her pops says $30 pump from pepboys, should i really push for the 100 it cost me at GM or let it slide cause there all the same?
Any advice is appreciated thanks
Corrected it was late

English please

I would go with an auto parts store pump over the stealership.
If you would look around online you could find one that is very cheap and has a lifetime warranty.
Why does it need a new engine? You could probably find a new engine at car-part.com for as low as $400 and install it yourself if you know how.