Bounce test is the down and dirty, the suspension should move, but if you try to bounce it just goes back to the start position. Rear shocks are easy to see, should be boge (sachs. stock), bilstein or Koni. KYB and others suck. Rear springs should be rust free, stock springs sag, look for the car sitting nose high.
Front struts look for leaking.
That's about all you can see, the front rubber A-arm bushings likely need replacing and the rears also can have issues. If the seller can't prove the bushings were done it goes on the to do list.
All this stuff can be fixed, just time and money.