ok Here is my guide to having a pure prayer rs account!
Normal Way- From level 1 do Father Areck's quest in Lumbridge and you level up to about 9.
Then kill chickens in the lumbridge coop and pick up their bones. Bury them every time you kill another chicken. Killing chickens is fast prayer experience because you can kill them in one shot as they only have 3 hitpoints. They also drop the normal bone. When you have reached about level 20 prayer, train your combat to 40 if it isn't already.
Once you are 40 combat get a brass key from the Grand Exchange.
Go to the little house on right of Barbarian Village.
Go down the ladder in the room and you find yourself in a room full of hill giants. These lumbering giants aren't usless as they drop big bones!! These bones give the most experience in the free to play world. Once you have killed many hill giants and gotten bored,
Make your way to the Bone Yard. The bone yard is north of Varrock in the wilderness. There are about 8 normal bone spawns there. This is great because you don't have to kill anything at all. Once you have picked the bones and buried them new bones would have spawned already. This basically means that you bury bones non-stop. This will level you up extremely quickly. IMPORTANT: Be careful of the menacing renevants wandering around ready to attack you!
You can level up you prayer in many ways even just earning money and buying big bones or little bones!
If you are a member use bones on an alter!