Estimated cost to replace front ball joints? recommend a mechanic? on 1996 Pontiac Firebird

I recently bought a 96 Firebird with great engine but front end problems.
My local mechanic did not find anything unusual except a poorly maintained vehicle and recommended struts, which I had him install. A few days later I started the car, put it in reverse but rather than motion there was just a sickening hard metal clunk from the right front. Upon inspection, the strut was hanging there and the wheel was separated from the axel, the chasis was resting on the tire.

1 answer
upper or lower ball joints?