I was able to book a hotel room on priceline for $40 a night at the Holiday Inn Select for the weekend. (bid $40 for a 3* in the Airport/Mall of America area). I've stayed there before and have been very happy, especially for $40. It isn't real close to downtown St. Paul, but the 54 bus is a great option as it runs from within a block or two of the hotel to the front doors of the Xcel. And metro transit buses are free on Sat. for St. Patrick's day. check the schedule at metrotransit.org Also, a cab ride wouldn't be too expensive, around $20.