Go to whiteline website. From memory the front is about 300 for the adjustable one which i recommend . The rear about $250
The rear 20mm is not adjustable the 18mm is. As for labour there is a couple of hours in removing K Frame etc so id say on the $200 side.
Also i would not be happy without doing a realignment as you disconnect the link bars etc. depending on which rubbers you chose to replace. For
the cost of em i would do em all.
Also i stick with rubber for your lower if you want more K's the eurathane ones tend to chew out a bit quicker cause they don't have as much give.