woodcutter is normally the most used in f2p but fisher makes like 50k per hour at lobs, miners decent aswell but its time consuming and ores aren't very stable atm any bot will make money though, in my opinion fighter bots the best made 150m getting 99 att and 99 str in p2p
You could try making a wcing pure and just chop yews or something. Or you could also make a mining pure, get 60 mining then go to the mining guild and use kminer to bot coal. Or you could upgrade the account and go bot at LRC which is alright money and can get you 99 mining.