Homebrew, yes, but admittedly I do not know a lot about it and have only bought a select few games that caught my eye, all of them being digital copies through GoG, XBox Live Arcade, or a few ROM downloads here or there. I wouldn't mind having a few of the Mario and Zelda homebrews on cartridge, though.
Repros, no. I buy the originals. If I have any repros in my collection, they were well-disguised and I have no idea, lol.