I paid $80 for a D60 with 3.73 locker from a '79 F350. It has a 30 spline carrier so I can slide my stock axles in after I change the housing ends. I might have $500-600 into it once I buy brakes and gaskets/lube/fittings. If someone doesn't have a welder and alignment bar then I guess there is $150 or so added to have someone do it. If I decide to upgrade to 35 spline I might spend another $600 for axles and a spool.

Not saying everyone should go with a junkyard D60 but it's a decent option for street/strip cars.