It’s everywhere, if you’ve been paying any attention.
SodaPoppin got all his stuff taken away in HC a while ago because he bought gold:
Flask of Pretrifcation recipe goes for 5,000 gold on HC servers. Tell me how you can reasonably get that without buying gold from bots. The problem has gotten so bad over there.
The biggest reason people buy gold is GDKP. That’s where it all gets spent.
Is there a reason to buy it otherwise? Everything else in-game can pretty much be paid for normally, even mounts. They’re not that expensive.
But a sought-after item in a 40-man is definitely getting bot-gold spent on it.