You'll have to pay for the cost of your own for things like buying a wizzy bomb or using the al-kharid gate. Dragon Slayer - Able to kill an lvl83 dragon with no range , but 15k (with an mage at lvl 33 and an air rune) however, in a position to not kill lesser demons
Because you're a non-paying player, I'll tell you about the best ways to get green dragonhide bodies. The largest exchange offers nats, and the bodies. While you'll benefit the most value from this, you'll only earn 20gps per alch. The maximum loss is 100gps per alch. The price of 55-99 high alching with 198k Alchs could vary between +3.9m to +19.8m. It will take approximately 200 hours.
Though, you'd have to get to 55 magic first. I suggest spending between 200-300k and 300k on fire strike or earth and then putting the rest of the money on lesser items. To reach them, you can use fire strike or firebolt to take on monsters. Since Monster drops aren't always predictable, I'm not sure what the cost would be.
You can also make use of curse to level up. for 99 that would cost you 17.9. For this to happen it is necessary to purchase 449k body parts and 898k water supply (don't use the earths; you only need 3 instead 2 waters so it will be more affordable). Be sure to have plenty of heavy metal armor and any other items that give a negative (-), magic bonus . You dont want your curses to effect the creatures, so you could repeat the spell on him. You will still receive the same exp for failing.