How much d o es it cost to get the ball joints replaced

I would expect to pay at the low end $300 to a high of $500 for upper balljoints. Plus, you will need a wheel alignment.

It really depends if it is the upper, lower or both. Did someone tell you they needed to be replaced?

Had all four ball joints replaced on my Crown Victoria earlier this year. Cost was around $700 with good quality aftermarket parts and including the alignment afterwards.