I've never had a ball joint replaced by a shop - I've always done it myself. That, and I've never replaced an SVX ball joint.
But it's gotta be less than $200.
Look at it this way. If it's not a ball joint or strut mount or tie rod end, then that's great. If it is, and you don't get it looked at, at some point when it starts virbrating at freeway speeds it's going to separate and you will lose control of the car.
That's why I recommend that you have it looked at immediately.