/facepalm
If you wish to spend 5 hours of intensive working to gain a miserable ammount of cash. Listen the posts above.
Otherwise, Monster killing or Clue Scrolls
1 - Get your combat up. I'd train my slayer along it, because you train three skills at the same time. Begining sucks, but when you're above 30-40, it's more enjoyable. At 55(?), you will find jellies. They're probably the best level 3 clue scroll droppers. You get one roughly around 100 kills. Plus they dont hit you much. Slayer is a great money maker, When I did 39 to 74 slayer, I made a total of ~5m+, And it was kind of quick. Well I was quite a no lifer but LOL.
2 - For someone who is low combat and low thieving, I'd suggest pickpocketing H.A.M. You will get junk, just toss it. Eventually, you will get level 1 clue scrolls. They're incredibly easy and short. On averge, I'd say 1/10 clues gets you a good loot. You might say ''Oh but that's not much'', well, I once got 10 of those in one day. 3 of them got me a total of ~900k, the rest was junk. You easily get 5 of them in one day
3 - When you'll reach level 80+ and alot of cash, Metal Dragon Hunting. They're on the Brimhaven Dungeon. Buy a ton of antifire pot and range them with a Rune C'Bow (with good bolts of course, ton of them) and kill Iron/Steel Dragon. You can get Dragon Items like, Dragon Med Helm, Dragon Skirt, Dragon Legs, Shield Left Half(worth nothing nowdays XD) and maybe even Draconic Visage. I'd say 70 ranged is required, else you wont be able to hit them much.
4 - If you're not much high Ranged, but want to kill dragons, Kill regular dragons. Like the blue ones. And pick up their Bones and Dragon Hides. Sell them after that. 500k+ can be easily made.
Have fun
