These favors / thank you gifts were a big hit at my daughter's graduation picnic. We had planned to serve cans of soft drinks, etc. during the party, so I went to a local craft store and purchased plain foam can coolers - sometimes called Koozies. They were very inexpensive - I got them for .50 each. Got them in her school colors. Also bought little foam self-stick decorations - hearts, starts, frogs, etc. We used a black Sharpie to write the guest's name on the heart, star, etc. and stuck them to the koozie. Then, we bought 2x4" clear address labels, and used Word to print "Thank you for celebrating (name)'s graduation!". I put a label on each koozie, then covered the label w/a blank clear label (to keep the ink from running when it got wet). We put all the koozies on a table, alphabetically, right next to the coolers w/drinks, and encouraged each guest to find their thank you gift. We wanted to do a favor that would be useful, and, this cut down on guests forgetting where they left their drink during the picnic. For those guests who did not want to drink directly from the can, we provided disposable cups that also fit in the koozie. These were a big hit and very inexpensive to make.