My favorite party favor of all time is the tetra pak because it's quick & easy to make, has an unusual surface area for design, and holds a surprising amount of treats. 4 ghosts fill up a sheet of 8.5x11 inch paper efficiently, so there's very little waste. Remember to print "Fit to Page" so it maximizes the printing area. Directions and pattern can be found on my blog post:

 

http://paperzen.blogspot.ca/2013/09/halloween-ghost-party-favor.html