You could also take on Green Dragons north of the Graveyard in RS Gold the Wilderness. You just need to bring the Anti-Dragon Shield, food and equipment. Don't carry anything of value so that you don't risk losing a bank on Player Killers. You might also consider farming in search of Void Knight Equipment because you won't lose it by falling victim to it while in low Wilderness. It's a great option for Dragon Killing and a safe one for wearing in this zone.
The bones you gather must be offered for sacrifice on the Chaos Altar, but it is a dangerous method therefore, don't carry anything besides the bones that you'd like to sacrifice. This is among many of the Player Active zones on Runescape and is located in the 38th level of Wilderness.
It is a sign that players from higher levels could challenge you. It's advisable to keep them in the banks and run the Altar running once you've got enough of the bones stored however it is up to the player to decide if they want to put your equipment at risk.
Another method of learning is to train through the Slayer. During your Slayer missions, you'll acquire a variety of Endorsed Monster Heads, which can be reanimated in the Dark Altar. Reanimated monsters killed will give large portions of Prayer experience but it is a less constant method than regular bone farming, and you cannot guarantee that you'll have enough Ensouled Heads to make it the level from 1 to 99.
It requires a lot of Pure Essence for RuneScape 3 Gold leveling purposes It is obtained by mining process and monster drops. The first method is easy but isn't very efficient, since you'd spend way too much time mining rocks which do not provide much Mining Experience.