If we're talking about d20 Conan as per Mongoose, you also need to keep in mind that the game assumes an episodic approach to the campaign. In other words, the games are intended to be inspired by how R.E. Howard's short stories are written. Thus, adventurers in Hyboria do not have a constant income, they accumulate wealth and then spend it all on whores, booze and lotus. Then they pass out in a gutter, wake up chained to a slave galley and the next adventure begins.
The game is pretty low wealth and assumes that people have nothing and will die poor unless they grip destiny by the throat and take what should be theirs! There is even a Will save for finding vast piles of booty (so...much...treasure....salivating). So, it seems strange that they would have a constant income.
Now, you can obviously divert from this however you like. But just my two copper pieces.