It was just announced recently and the beta went live today. Basically you can put money onto your steam account in amounts of $5/£4, $10/£8, $25/£18, $50/£35 or $100/£70, and then use it whenever you want. Right now it doesn't seem that you can buy them for friends but I expect this feature might be added.
Here's some potential uses:
- Giving your friend $20 on steam for their birthday instead of trying to guess what game they want.
- Steam giftcards.
- Loading $20 into steam every month and only purchasing through your steam wallet to help prevent impulse game buying at 3am.
- People under the age of majority can have money loaded onto their account and then they can buy whatever they want, no more bugging your parents for a specific game.
I realize that there might be a minimum value due to transaction fees but I'm hoping that they may open it up to custom values, like being able to put $47.60 into your account if you want, so we don't end up with the "I have 0.35 intergalactic space bucks floating around in my steam account and can't buy anything or get it back" issue. You can see the beta
here.
On another note, it says "Funds in your Steam Wallet may be used for the purchase of any game on Steam or
within a game that supports Steam transactions." I don't recall any Steam games having micro-transactions in them or the ability to buy DLC from within the game, so this sounds new.