You get money into the treasury when the world leader sets taxes. Tax-Money is currently, to my own knowledge, the only way to get money into the treasury. From there you can distribute or dump it as well.
In the following link you find a economy-solution to a capitalistic playthrough/playstile with a researched pricing document. The pricing is considered fair and leaves room for your own ideas. Just edit the core-ressource price-numbers and adjust it to your personal liking and/or economy of the server.
This sheet will not work within any other form beside a capitalistic one. Still it may give kind of a reference. Enjoy.