The cost to have a mechanic replace U Joints on a vehicle ranges from $150.00 to $250.00 depending on the vehicle and the cost of the shops labor charges.
Replacing U Joints takes between 1 to 2 hours and some shops charge $50.00 per hour while other shops charge $100.00 per hour.
The U Joints themselves are usually $10.00 a piece to as much as $50.00 each but some shops may charge a markup price to profit off the parts which is okay.
If you can do the job yourself you can replace the U Joints for the cost of the parts and your time.
Just make sure you do not bend the drive shaft because if you do then your vehicle will vibrate.
You'll need to hammer the U Joints out and then hammer them back in.