94 BMW 218is strut mounts and bushing repairs needed?

What is your question?

My 94 BMW 318is has been experiencing a rough ride for the last month. Every time I go over big bumps, -- clanking noises, kind of Iike a few wrenches bouncing around in a tool box -- come from my right rear tire. A softer hissing sound happens over smaller bumping like someone tapping a cymbal being lightly hit. I went to one mechanic and got quoted 500$. I'm going to two other shops tomorrow. For other quotes. Would it be good to buy my own parts to make it cheaper? Is the servicing what costs so much? The parts seem relatively cheap?