Issues with gold

The problem is that I have one character at level 90, but now I want to level up another character but I don't have enough money to fly, for example.

Can somebody tell me how Can I earn some money for my new character?

If there are some mistakes, sorry for my English. Bye ^^

Go solo Balck temple 10 and 25, also farm naxx, might be harder if youre not geared. But farming old raids will help you acquire more than enough gold

I will do WOTLK and Cataclysm raids then.

Thanks so much ^^