This is a bit more like hacking but isn't as it uses server-side thing. Many people already know CheatEngine and T-Search. You will surely learn how to use it, the tutorial is included with the software. No scams, no hacks, no viruses. You can already see many people use it:
[url]www.cheatengine.com[/url]

-My recommended way-

Scan the money you gain at the end of a quest.
Example: You earn 300$ at the end of a quest. When this page appears, first scan the 300$ and change the value (Not too high). You'd get 3 to 10 times the earning of the normal gain.

Search on Youtube to learn how to use it too.