Virtual 'credits' for Facebook have gone on sale in the UK this week.

Facebook Credits, which are available form Tesco and Game, can be used to by virtual gifts on the social network, for exmple in games or to leave on friends' profiles. They come in denominations of between £5 and £25.

Alternatively, social networkers can purchase credits themselves using the 'Payments' option on Facebook. However, the social network said the credits purchased in-store were a better option for younger users of the site.

"By using Facebook Credits as an alternative payment option, they [parents] can control the budget their teen has to play with games online and also avoid fees or overpayment on their credit card. It's a real plus in terms of security and peace of mind," a Facebook spokesperson said.

Euan Ballantyne, head of cards at Tesco Bank, believes the virtual credits are "an ideal Christmas present."

See also: Facebook and MySpace plan joint announcement today