"Erosion discs", and where to buy them

So, came across a terrible shill video from "Shop tool reviews" pushing diamond metal cutting discs for your angle grinder. Don't buy them, they're shit. Instead, save money, and do two things:
Learn to use cutoff discs properly : • This Trick makes your ...
Buy discs from Action, Aldi, Lidl or other equivalent super-cheap hard budget stores.
I wouldn't recommend buying tools from them, but slitting discs at about 1/20 of unit prices for brand name discs? Hell yeah.
I bought all this crap with my own money.