I just finished the rear on my 2018 2500. I went to NAPA and bought mid-priced pads and rotors. Have a second car available if you need to return to the store in the middle of the repair. Here in upper central NY State, road salt and rust causes pads to not slide like they are suppose to and they bind up. You might not need new rotors if you don't get a lot of rust in/on the brakes where you live. A trick I read somewhere when using the C-Clamp to press the pistons back in; open the brake bleeder and slowly press the old brake fluid out into a small cup rather than back toward the master cylinder. When you bleed the brakes during reassembly, use a turkey baster to suck as much of the old fluid from the reservoir, and refill with new fluid. If the rear disc won't pull off, back off the E-brake adjuster. You need to clean (scrape with a file) the caliper slider surfaces real good to get the rust off, especially the rust build-up on the surface under the stainless slider pads. Put a thin layer of brake grease on the pad ends and caliper bracket sliding surfaces. And, when you put it all back together before the caliper, make sure the brake pad "ears" slide without binding. The springs on the pads are supposed to "lift" or pull the pads away from the disc. When you R& R the slider pin grease, it is tricky to put them back in because of the air bubble that gets trapped. Clear the grease off the flat surfaces on the pins might help and spin the pins when you finally get them back in. It is not that difficult, leave yourself a lot of time, and check yourself as you go.
