Keeping up with a crafting wizard for the sake of gold is not difficult, but it generally requires you spend skill points and feats on things you would normally not. In most cases the wizard can match or outpace you in anything crafting related but as they are too busy making magic items you can go ahead and profit elsewhere.
Taking the Feat Master Craftsman would let you get into the crafting game, as stated before it would require 2 feats but being able to craft and enchant your own weapons/armor/trinkets is satisfying. More so if you happen to be a master tinker gnome and use stupidly exotic weapons just for fun.
A character with the Master Alchemist feat, If supplied with the raw materials could easily make a gargantuan amount of gold by crafting high end poisons.
The feat reduces the time to craft doses of poison by a factor of 10x (Int mod) so a relatively intelligent (Say 16) non-magical person could craft poisons at a rate of 30x a normal alchemist so long as he had materials and time.
In game ramifications for being a master craftsman of assassination tools can easily outpace the value of the feat if your DM wants to punish you for it. so make sure to get an OK on this sort of thing before taking it.
Another option is the feat Master of the Ledger.
you invest money in towns, hire couriers to collect your dividends and wait patiently as the money accrues. Really, that is all there is to the feat. You get money at no risk to your own capital. Barring destruction of the town you invested into this feat will eventually outpace magic item creation in raw gold earned due to the sheer size of the material plan and the significant number of cities and villages in such a place.
Disadvantage to this is becoming a merchant with a shiny knife instead of being an adventurer as the in game questions of organizing your fledgling merchant empire become increasingly important.
An interesting concept but just like leadership the feat can easily break games if it is not kept in check.
