Farm knowledge, pick up anything that drops, post it for sale. You'll figure out what sells pretty quick, and you can post 20 (non-VIP) or 40 (VIP) stacks of items per city.
Farming knowledge is basically finding mobs you can kill, getting abilities, and with the new abilities, finding new builds allowing you to kill new mobs.
As a cryo mage, I suspect you could kill most bandits (including the pyromancer, but watch out for the cyromancer). They drop a good amount of gold plus other useful things (including divine rewards). You can find them in the yellow combat areas.
Anything you get from divine rewards will either be gold, or something you can try to sell.
Note that as a mage, you don't need a house or anything beyond primitive gear to farm knowledge solo. I'm not sure how far you can go without gear, but I'm rank 30+ and naked. (I consider finding ways to win without gear an interesting challenge.)