Bond

A bond is an in-game item that allows a player to pay for selected account-related and out-of-game benefits such as membership, Runecoins and Spins with in-game resources.

Tradeable bonds may be traded to other players and sold on the Grand Exchange; however, when the transaction is complete, the bond will become untradeable. A bond is always bound to a player when it has not been redeemed or traded to another player. It is always kept on death, even when inside the wilderness.

Uses
When bought using real life currency, bonds are tradeable. Once traded to another player for an in-game sum of money or items they become untradeable. Bonds can be made tradeable again for a payment of 10% of their Grand Exchange value (i.e. 10% currently being coins).

At any time, whether tradeable or untradeable, bonds can be redeemed for one of the following:
 * 14 days of membership (Counts for oldschool as well enabling F2P in oldschool)
 * 8 Squeal of Fortune spins
 * 160 RuneCoins

Bonds can be used:
 * To trade with other players
 * By selling for in-game money
 * To buy RuneFest tickets (not currently possible)
 * To charity via the Well of Goodwill when it is active (currently active to 30 November 2013)
 * To buy Runescape Membership [Premier Club]

Price per unit
The below prices are subject to change, depending on a bond's Grand Exchange value:

Charitable donations
Jagex donate approximately $4.70 per bond put into the Well of Goodwill, slightly less than the purchase price. A selection of charities benefit from the donations.

Trivia

 * Despite being tradeable, bonds cannot be placed in the party chest at the Falador Party Room, stored in the treasure chest from Carnillean Rising or a beast of burden; they may also not be staked at the Duel Arena or in Conquest; they may not be fed to a Baby Troll.