Dragon bones are associated with the Prayer skill, and are dropped by most adult dragons. Dragon bones give 72 Prayerexperience when buried, 180 Prayer experience when cremated, 288 Prayer experience when offered at the Ectofuntus, or 252 Prayer experience when offered at a gilded altar with 2 burners lit. The relative ease of collecting dragon bones, combined with the amount of experience earned from them, makes them widely viewed as a fast, cost-effective way to train Prayer. Free players can only obtain and use dragon bones by killing green dragons and iron dragons in the Daemonheim dungeons. They cannot buy, sell, or obtain any of these bones outside the dungeons of Daemonheim.
Members can also get dragon bones as a reward from the Soul Wars minigame by selecting the 'Gamble' option when choosing rewards. If a player gets dragon bones, they will likely be noted in quantities of 11 or 22.
Green and Blue dragons are the weakest types of dragons, resulting in dragon bones mostly being accumulated by killing them.
Green dragons are the lowest level dragons in the game. They can be found in various places in the Wilderness, as well as in two locations in the Chaos Tunnels. Green dragons in the Chaos Tunnels are grouped together with Baby black dragons, while players may be attacked by Player Killers while fighting green dragons in the Wilderness locations.
The high value of dragons' drops (bones plus hides every kill for chromatic dragons) makes dragon-hunting a highly profitable combat activity. Players can make 120K to over 1M coins per hour fighting green dragons, depending on how fast they can kill the dragons and bank the loot. About 35K to 100K can be made per run on dragons (depending on inventory space /B.O.Bs), and more if more valuable items are brought back as well.
While gilded altars give the fastest experience, some prefer to use the Ectofuntus due to the fact that gilded altars give 36 less XP per bone. Although it's slower, the Ectofuntus gives more experience per bone, decreasing costs, and eliminates the need to obtain marrentill and/or find a house party offering an altar.
A player choosing to use dragon bones all the way from 1-99 Prayer, using a gilded altar with lit burners and no other experience boosts, would, if all the bones were bought at the current medium price on the Grand Exchange, spend 154,499,387.
Additionally the first two bones would take them straight to level 6 Prayer.
Using the ectofuntus would cost 135,186,964, but would take far longer to do. Simply burying the bones would cost 540,747,853.