"UPS" = "Uninterruptible Power Supply"

http://en.wikipedia.org/wiki/Uninterruptible_power_supply

Everybody sells them ... office supply stores, computer stores, etc. They are often on sale, sometimes at ridiculously low prices. For example, I bought two APC 500VA units for $12 a piece. That's right - TWELVE DOLLARS each. Staples Office Supply store was clearing them out because the new year model was a 550VA unit. Plus, they had a pricing mixup - I pointed this out to them - but they said "Wow, this is your lucky day. We'll give them to you for this price anyway." I was quite happy about that!

http://www.newegg.com/Product/Product.aspx?Item=N82E16842101343

http://www.bestbuy.com/site/olspage.jsp?...d=1188559784051

Also check Office Depot, OfficeMax, Staples, Costco, etc. Circuit City might have a good price on one since they're going bankrupt. But you have to watch those Going Out Of Business sales ... sometimes their "discount" prices are HIGHER than everybody else. Don't be fooled by the 50% off signs. Do your homework first.