Jarred Cool

I just got my 2001 Miata and I noticed some slotted and drilled rotors and brake pads for sale for cheap on Facebook. I really want to make the upgrade even if they're not name brand (since they're a good price), but I also want to finish the brake job and put in new calipers. I've done brake pads and rotors before on other cars, but I was wondering how I can find calipers that work with the upgrade that aren't too crazy expensive. I assume not all calipers fit all rotors so what should I look out for? Is fitment based on brake diameter? Maybe thickness too? Are rotors overly difficult to replace? Are there any hidden things I should be looking out for? What are decent calipers to get that aren't expensive? I'm handy enough and have a good selection of tools, but I'm definitely still learning with this car. Any advice or tips definitely welcomed! Thanks