There's a lot to replace if you're talking suspension. If you're talking just shocks and struts, I brought mine back to OEM spec and cost me a little over $500 for both front and rear . . and I did the work myself.
Then there are ball joints, control arms, bushings, and sway bar parts. Your best bet is to get the lube job first, and while they're doing it, ask them to let you know if they see anything that needs replacing. By the way, the squeaking could also be the parking brake.