Geocaching.com
Geocaching is a game where people have hidden items around the world for others to find. What they do is document the positional coordinares (latitude, longitude) and post it on the Geocaching website. You can then take your GPS device and go to the exact coordinates to find the hidden item. Common courtesy is that you bring a different item to leave in place of the one you take. Some items will be as boring as a pencil, while sometimes you can find gift cards...anything someone decided to leave.
Price: $0
Location: Anywhere
Cheap and fun things to do around Minneapolis/St.Paul