Killing Dragons is most likely the best way to earn money from Skyzhay's blog

Killing Dragons is most likely OSRS GP the best way to earn money at the moment because almost anyone with decent stats can kill dragons. If your situation is similar to your skills, it's a piece cake.

Your options are green dragons, which are located at the Wilderness as I'm sure you've guessed it's quite easy to find an empty planet because most people don't kill Greens out of fear of getting PKed; Blue dragons are extremely easy killing, Taverley tends to be crowded as is the Heroes guild but it's not impossible to find an uninhabited world. W117 Heroes guild is usually empty. If you are at least level 60 in Dungeoneering you can access Taverley resource dungeon.

Red dragons: Not recommended as Red dragons can only be found in two locations as I understand it: Red dragon island in the Wilderness and Brimhaven Dungeon, both of which are far from a bank Dragons of the Black - Taverley is crowded everywhere I am not even thinking about it, so Zanaris is the best option in my opinion.

Metal dragons - There's not much to talk about here All Metal dragons are located in the Brimhaven dungeon (Mithril dragons being the only exception) and aren't too difficult to kill. They also drop decent drops. Frost dragons - 85 Dungeoneering required so it's not really an choice for you now unless you feel like training Dungeoneering. You could also earn money from Slayer however, unless you're getting regular tasks with Dragons I'm certain that you'll make more money simply by taking out Dragons.

What Silv suggested are all useful cheap OSRS gold suggestions. When I was at your level I did Experiments. From 60-70 and took me about three days. It was boring because you're not really gaining anything but experience there though.