Ok this is a good P2P money making method for Runescape. You should be able to make somewhere around 500k an hour doing this and it requires no skills. First, what you want to do is head to the swamp north of Tree Gnome Stronghold, almost right to the west of the grand tree. The easiest way to get here is to teleport usingthe spirit tree.
When you get there just make your way around and start picking up all the swamp toads. Getting a full inventory is really quick, each toad is worth 650gp + so a full inventory is worth over 18000gp which you can make in no time. There is a bank just to the south of the Grand Tree.