The retail roll-out of Facebook Credits gift cards is continuing today, with the company announcing their availability in three more chains: Safeway, GameStop and RadioShack. The timing suggests that Facebook wants these cards all over the place before the holiday season gets underway, and people start looking for gifts that their social game-obsessed friends and relatives will appreciate.

For those not familiar, the cards allow you to buy Credits in $15, $25 and $50 increments. Scratch off the back of the card to get a unique secret code, then enter it in the card section of the main Credits purchase interface on the site, and your account will gain the amount the card is worth.

Following the efforts of social gaming companies, and other digital entertainment providers before them, Facebook began introducing the cards in early September of this year – Target was the first retailer to get the currency, Best Buy and Walmart followed late last month. You can find the nearest stores carrying Credits here.

Beyond serving as gifts, the cards also allow people without access to credit cards or other online payment options (especially teens) instead buy Credits using cash. The point is to help increase the volume of Credits on the platform — a larger effort the company has had going for months.

Until the past year, developers with canvas Facebook applications deployed their own currencies. Facebook has slowly been requiring all of them to transition to Credits, though, and at this point most large and mid-sized developers have moved over or are in the process of doing so. While the company takes a 30% cut of Credits revenue, it thinks that between its brand, the integration of Credits within the core site features, the increasing number of payment options (like the gift cards) can together combine to make the currency more lucrative for developers.