What is a good affordable distortion amp for stoner music

[MrShake]

OP, when you say "distortion amp" and talk about your current amp's gain channel is "buns" (which I'm going to start using whether that's truly slang or not), I'm assuming you're looking for something that has its own crunch/dirt onboard. If that's the case, I don't have too much to offer, and wish you all the luck.

If you're willing to get your gain with pedals through a clean amp, some of the old Peavey heads like the PA are dirt cheap ($120 US?), loud as hell, genre-appropriate, and eat dirt and fuzz pedals for breakfast. Pick the head (Standard and Musician and Bass will cost a bit more than the PA, but still cheap), pick your cab for scale, and turn it up loud.

Either way, happy hunting!