They are 4 ways in which i will tell you how to make easy money. 3 of them take time but yield amazing results. The fourth takes fasr less time but there is combat involved
Kill cows for their hides. "Yawn" You have seen this everywhere! But there is something to it. Buy or kill cows for hides. Then take them to Al-Kharid(Its good if you have done Prince Ali Quest so as not to pay toll.) and get them tanned for 3gp each into soft leather. Then sell on G.E! It wont be good with 1 or 2 hides. Start of with a decent amount and you will be raking in cash in no time!/check prices on G.E if you don't believe it will work/
Buy or mine clay. Get a decent amount and then get lots of buckets and fill with water. Simply mix and you have soft clay! The best thing is that you won't have to move from the G.E at all! Just buy it all!
Get coal and iron. You need to be able to smith steel and you need good money to start this off. Like 100-200k. Buy coal (500) and iron(250(iron should always be divisible by 2 from coal)) and store them at bank. Go to Al-Kharid and run to and fro from the bank and furnace making steel. Very profitable when sold on G.E!
The combat method. Take a brass key, go to edgeville dungeon and kill hill giants and hobogoblins. They offer limpwruts, b bones, runes and other good stuff. Easy 20k per 15 mins with the right combat level!