The Restless Ghost is a quest that provides you 1,125 experience which allows a player to raise Prayer from level 1 to 9 upon completion. There are no requirements to begin this quest (although melee defensive armour is useful against the skeleton) and is strongly recommended for beginning players as it provides a fairly decent amount of experience points for relatively little effort.
There is a place within the Wilderness where many bones do spawn, no killing required. Big bones also spawn here too. This place is called Bone Yard and it's directly north of Varrock. Very few Big Bones spawn here (however you can pick those up and sell them if you'd wish). The main goal is the abundance of regular bones. There are lots of them lying on the ground with a relatively good spawn rate.
- Food (optional) - There are multiple level 20-22 skeleton mobs in this area. Be sure to bring enough food to last for a while if you do not wish to fight them.
- Armour - Since these mobs are there, it is recommended that players wear armour they do not mind losing.
- A weapon (optional) - If you choose to fight these mobs you can also gain a decent amount of experience just from that, they also drop bones.
There are multiple strategies you could use for this method. Any way works, whether one works better than the other, that's up for you to decide.
- Run in and collect bones (without burying)
- Run out and bury the bones in safety
- Fight mobs to obtain their bones as well (a higher combat level would make this easier)
- Bury all bones
You can always find what works for yourself as well.
Many low level areas consist of people killing mobs. People often do not pick up the bones which lie on the ground, therefore there is often an endless supply of free bones.
There are always more spots, but these are amongst the most common spots for people to be leaving loot on the ground.