I'm not certain why you would need a USB putting green unless you are a victim of office boredom. Well, assuming you can keep it from your boss, it does seem like something nice to have.

Personally, I wondered why someone would need an item like this to be USB powered, but I believe the extra USB power is there to return the ball. Not like I couldn't use my other hand to do that or anything.

The USB Putting Green comes with two putters and 6 mini-balls. You can get it for about ten pounds. Not certain what that translates to, but maybe you might like this.

Via Everything USB