pressing in ball joints isnt too bad. as long as they go in straight. if i didnt have my own press, i'd say it is worth the $8.00.
it is definitely worth it for the bushings.
supposedly there are special tools for doing the bushings, but i have never seen anyone use them. only pictures in service manuals.
if the bushings are not seized (which they will be) you might be able to get the second one out, and the first one in with a bj press, but otherwise the control arm shaft will be in the way, and the bj press probably wont have the correct diameter collar you need for bushings anyway.
tools i typically must use for contol arm bushings-
air hammer w/ chisel
4 lb sledge
excellent pair of channel-lock pliers
hone, file, or emerycloth
different diameters and lengths of wood and tubing for use as press collars, and a spacer to keep the arm from bending.
$8.00 apiece is a small price to pay to not destroy your control arms or new bushings.
the ball joints are easy, esp. with air tools. but you should have a partner to help you hold everything in place while you line up the press and fittings.
the upper ball joints are riveted in origionally (drill out rivets), and the new ones bolt in.
you will need to grease the ball joints before you drive it,
and you will need to tighten the new bushings to specs only After the car is sitting at ride height.
sorry if this isnt the info you're looking for.