Jfro: Thats comparing apples to oranges though... buying used from a third party is not the same as buying brand new. Getting them for $80 from a private party isn't bad at all... but $120 is a HELL of a deal
brx: These cover the front, but you can do one of two things in the rear... either use the washer bolt trick, which Ingalls has a product to do this.. (and before a bunch of people jump down my neck and say that they can get the same stuff at a Hardware store or something, that is fine and dandy for you... These are pretty inexpensive themselves as well, but with these at least they are made for vehicles with the proper heat treat and coating (VERY IMPORTANT so that they don't rust out or anything).
Anyhoo, the second option is a forged upper link that replaces the stock upper suspension arm. This is actually the BEST method, because the links are forged and way stronger even than stock. And you can of course get them with polyurethane inserts instead of rubber. The K-RX we just got done with got front balljoints and the forged link in the rear.
If you want rear bolts or links also, just take part in the GB that JonnyB is doing, and we'll be sure to try to hook you up accordingly as well with the rear joints if you need them
The balljoints allow camber adjustability without altering your stock bushings. Also, if you have a car that is lowered pretty decent, and needs a good bit of adjustment, the balljoints allow you to get the adjustment you need without the upper control arm hitting the frame of the car (which will happen with the adjustable arm mounts if you have to go too far on the 88-91 CRX/Civic platform... just not enough room under the fender well for much adjustment with the control arm mounts.