Use a sandwich bag or a similarly styled bag purchased from a craft store. You can use stamps on the bag or punch shapes on the edges to jazz it up, whatever you like. You'll need string, yarn or ribbon. A small piece of tape or staple and a gift tag if you like.
Open the bag first (I always forget to do this)close it and then make a few accordion folds. You can add the gift to it now and refold the bag.
Now you need to make a fold at the center of the bag and bring the sides up together. Tape or staple together on the back side and slip your ribbon or yarn through.
Tie into a bow and add a gift tag if you choose to. Beware! Some people like the gift bag more than the gift!