This is what I think is one of the best ways to make money in Runescape, in free to play(f2p) and pay to play (p2p).
First, I'll start with free to play players. The best money is if you have a 99 skill in almost any skill, but if you're more of a “noob” and have lower skills, then you should get “Wines of Zamarok” The Wine of Zamarok respawn site is located north of Falador, close to the wall that separates Taverly from f2p areas, and to the left of the Goblin Village. The Wines of Zamarok are guarded by several zamarok worshipers, which you have to kill if you want to take the wine. But, there's a way around this. Take an air staff, and 28 laws. I buy laws 1k at a time for 300k. At the end you make a good profit… So…take the air staff and the laws and walk/run to the respawn site. Use telekenic grab with the wines (you need 33 mage to do this). The wines respawn about every 15 seconds. After you get about 1k wines of zamarok, which would take about a week or so, go to the Runescape forums, and search for people buying zammy wines for 1k, or so, each. Sell the wines to them. If you bought 1k laws for 300k, and sold the wines for 1mil, you make a 700k profit, in a very short time. This is what I think is the best way to make money in f2p.
For p2p, if you don't have any 80-99 stats, then you should do…LAW RUNS! Yep, LAW RUNS! Not many do it, for they have not heard of it, or they don't think it's a good way of making money, but I always see level 100s+- doing it alongside me. So…how do you do it? First, mine/buy 27 pure essence… it's very cheap… Once you have them, Go to Draynor Bank. Once there, take off all weapons, armor, staffs, etc…anything that could possible help you fight…Once done, take the 27 pure essence with you and go to Port Sarim, and talk to a Monk of Encarta. Tell the monk you want to go to Encarta, and once he searches you, you can go. Once in Encarta, go to world 66. This is where LAW RUNS takes place. So…once in world 66, follow the large amount of people there to the LAW altar. There, you will see high levels wearing Red colored (Zammy) Robes. When they say “Open” quickly trade them. Offer them the 27 pure essence, and they will trade you 27 laws, and 27 noted essence for it. Go back to Draynor bank, and store your laws, turn the noted ess into unnoted, and repeat. In an hour or two, once you get 1k laws, you can sell them for 350 each, or hold on to them, and get a large amount, and try selling on Forums for more money.
These are a few ways I used to make a lot of money the past few weeks. Hope you like them. =)