Lower ball joints are not available seperately from the vertical link at the dealer thus the high price. Aftermarket does offer seperate balljoints and a standard press will work. The biggest problem with that is the wheel bearing/hub assembly has to be removed from the vertical link to do the pressing as it blocks access to the balljoint. The hub is usually seized in the vertical link and any beating on the hub, link, bearing runs the risk of damaging the ABS sensor or bearing. I've replaced many, many hubs on cars that had balljoints replaced at independent repair facilities. Not knocking your tech just saying be careful.

 

ive had also what real tech mentioned of other garages. one of my customers went to a place and got a aftermarket balljoint installed on a S and 2 weeks later came to my dealer on a tow truck . new ball joint let go on the highway . needed new rim control arms vertical link ended up costing 3 times as much..