As players level up they start gaining greater amounts of gold per “adventure tier”, at the rate of roughly from 10^0 to 10^3 at the top tier. This leads to the players quickly gaining far more gold than they could ever need for common goods, standard equipment and weaponry.
What to do when that happens? What to do with all that gold?
This post on stackexchange.com is one of the more creative ones I’ve found on this matter and should server as a solution to that problem in most cases.