I changed my rear brake pads last night. Not too bad. I used a ceramic mix from "Gold" from Advance Auto. They cost about $41 for all 4 rear pads.
They are right and left specific....The inside pad was worn to the metal. The outer one looked like 50%.

When i had my axel replaced the dealer over torqued the lug nuts on the right wheel and I had a hard time getting the lug nuts off.
I swear that is why the rotors warp. I torque mine to 100, using the star pattern, and no warping at 62,300 miles.