From lvl 85 and up you can start to power mine coal (im lvl 88 and it really goes quite fast). If you find a world without many people, the mining guild is a great place. But also look into the skeleton mine in wild. Its farther away from bank, but no competition.
Bring lots of food and have at least 2 other people drop food while you are fighting so you can pick it up and eat. Thats my only suggestion if your f2p