Prayer provides players with a little boost in combat in runescape
As a little side note from in-game questions, most players assume this skill is the most expensive to train, so I hope you are up for the challenge. Getting 99 Prayer requires a strong mind for beating through boredom and also requires a large amount of runescape gold ... if you can provide both the Cape and the emote are both yours for a little extra 99k that shouldn't be much after getting 99 Prayer in the first place.
As of a March 2009 update a 'quick-prayer' button was added near the mini-map in the upper right corner of the gameplay screen. A player can select a prayer, or in some cases prayers, that will turn on when they select the quick-prayer button. This makes it so the player doesn't have to switch to the prayer tab and select the prayers while in combat.
Thanks to an update, players using an altar in a player owned house (Post 13-14) can now select 'offer "X"' bones to reduce the number of mishaps when trying to quickly train prayer.
When your prayer drains to 0 you must pray at any altar that is scattered around Runescape to replenish your prayer.