I got my newest set of rotors at Napa for less than $40 each. Pads range anywhere from $15 to $50 a set. Whatever you do, don't buy the performance friction pads at Autozone...they're stronger than the rotor and therefore the rotor will wear before the pads do.
Pads are simple to change.
-Jack up front wheel
-Remove wheel
-Use a punch or larger screwdriver and hammer to drive out the two pins on the caliper. It's fairly easy to see how this works...there are two little bumps on each end of the pins to hold them in place. Just angle the punch or screwdriver the right direction, pop them a couple times with the hammer and they will slide right out the back.
-Remove the caliper...you may have to tap it with the hammer, but it'll slide off pretty easy.
-Set the caliper on top of the shock mount or wire it up to the spring or something...don't let it hang.
-Take a large c-clamp or clamp of some sorts to press the caliper piston back into the caliper...stop just before it becomes flush with the caliper. Use an old brake pad or piece of steel across the caliper to ensure the piston goes back in straight.
-Take off the old pads and then put the new rear one in on the back of the rotor and the new front one on the caliper...it should have clips to hold it in place. (rear being the back of the rotor, front being towards you..)
-Replace the caliper, pins, wheel, lower the vehicle, tighten lug nuts again, and REPEAT on other side.
My advice is to go ahead and replace the rotors and then plan on changing the pads about every six to eight months. 92's have horrible brake systems....I've went through several rotors and too many sets of pads to even count. Don't tell your parents this of course...cause the explorer is an awesome vehicle...and not really that hard to work on.
Randy