Car is riding lower than normal and takes bumps extremely rough, where it constantly bounces up and down, making it it a very uncomfortable ride. What could this possibly be, and how much would it be to fix? Thanks!

Sounds like you need new socks and springs.

Call Milt's Service Garage in Vallejo. You probably need new struts.

Sounds like your struts/shocks are worn out and overdue for replacement. Worn out suspension can also damage tires and steering components. A careful inspection is recommend so you can properly address the failed components to restore the ride comfort and handling.