Cost effective UPS?

My area gets lots of short power outages during the summer (usually no more than a minute or two), and I'm at the point where I'm ready to drop some cash to avoid the interruptions.  I've got a fairly modern gaming computer, and just want something that will buy me a couple minutes to ride out short outages and avoid losing work.  What's a good low cost UPS for this?  I don't need many outlets, all I have in my current surge protector is the system, monitor and modem.