I found the best way to make money on Gaia without investing a lot of cash. The way to get money is a very fishy one. You get throw aquarium tanks.
Do you know the minigame Booty Grab?
Just tap some tanks from other Gaians and maybe you have a bit luck to get the Booty Grab bonus game. There are dedicated threads of it in the forums. Check them out and tap them like crazy.
It really pays off. I almost made around 30k gold today with Booty Grab.
How about you tap my tank too? Just do it ;D
WIN 1000 EXTRA GOLD WITH BOOTY GRAB!
This is how it goes:
Tap my tank, play booty grab, make more than 2000 gold in a game, make a screenshot and send it to me (PM/Comment) -> Win 1000 GOLD BONUS!
Go go go and good luck!