Easy money
Go to Port Sarim, west of Draynor village, and ask one of the people in the blue uniforms to go to Karamja and pay them 30 GP. When you get there, walk off the dock and you should see a house. Enter the house and talk to a man named Luthas. He will ask you to pick bananas. Answer "Yes", pick bananas, put them in the crate, then talk to Luthas to collect your moderately earned 30 GP. If you would like more money in multiples of 30, ask him to get another 30 GP for doing the job again. Stay here for a long time if you need to spend several thousand on items.
Go to Port Sarim and do the banana thing and put a bottle of rum in the crate then go in and collect your GP. Then go back outside and to Port Sarim get a white apron and go get a job in the grocery store at Sarim. Search the crate in the back and take the rum and some bananas. Then go to the bar in Sarim, give the drunk the rum and then, when you are done, go up to varrock or someplace and sell the bananas.

Computer
First you put moneybags on your list. When it logs in, a computer will tell it your serial number and password and it print money on it like anywhere from 60,000 to 1,000,000,000 GP or you get rune item. He is usually on on saturdays and a few times during week. You can only do this 2 times on each serial number and if you do it more times you get cut off!