Well, I have not paid to have this done, but here is my thinking:
labor cost to remove and install 2 balljoints on same side: 3 hours labor @ $65/hour = $195
material cost for 2 ball joints (with markup): $125
labor to align front end: $50
misc. shop charges: $50
Total bill: $410
Since my estimating may be grossly off, figure anywhere from $350 to $500 for one side.