Is it 2wd or 4wd?
I used to be Front End Tech for a few years. Did them everyday, all day. And alignments. Went to school. I am ASE Certified in Brakes, Front End, Engine Performance, Electrical Diagnosis.
If you dont have a Ball Joint Press Kit, or a Air Hammer, or Air Tools. I would suggest finding a good shop. $600 is insane.
Labor for 2wd. One side, Lower is .8 Hr. Both sides, lower is 1.6 Hrs. Depends on how much the shop charges labor.
Upper and Lower labor total: 3.7 hrs. Which I can knock it out in under 1 hour.
Common is $75-95 hr. Say they charge $85 an hour. Total of $136 for labor. Maybe $100 for parts for the best. Looking probally under $300.
That does not include a alignment. Lets say, $60 for a 2-wheel Alignment.
Of if it's 4x4:
One side for lower, 2.6 hrs. For both sides, lower, 3.8 hrs.
Both sides total, at $85 hr is $323 for labor.
Upper and Lower labor total: 6.4 hrs. Which I can knock out around 2 hours.
Still, not close to $600. I would only pay $600 if they have both upper and lower ball joints, alignment. And replaced with Moog.