My rear passenger side tire makes a horrible knocking sound anytime I put light pressure on the brakes, or have a good jolt to the suspension, I pulled the tire off and it seems like the caliper itself is loose on the disc, I can slideit back and forth atleast an inch with 1 hand.

As in I can slide it around left to right on the disc, not just piston play on the caliper. Im not car expert but I like to fix things myself, but Ive never seen this before, and from what Ive gotten out of this site already I really wanted some advice before I started wasting money.

Anything would help, is it just some kind of bad bushing?

1995 Eagle Talon ESi
Cold air intake
Exhaust
Ebay Halo's

This sliding is it side to side (like piston play) or front to back (radially around the brake rotor).

If its like piston play..are you sure both pads are in there?

If its front to back you probably lost both bolts that hold the caliper to the caliper bracket (on the back side)(the 2 bolts that go through the rubber bellows.)

1998 dodge avenger 4 cyl AT
Mods are:
Not enough

and if you can take some pictures of all angles. it will be obvious from the pictures.

1998 dodge avenger 4 cyl AT
Mods are:
Not enough