thin scrapbook or tissue paper
Pull the center of your bic pens out. Cut a strip of paper just the length of the pen and about 1.5 inches wide and secure to the middle of the ink barrell with a piece of tape. Hold the pen end while rolling the paper around. Make sure it is nice and tight. Insert back into the barrel of the pen. It will be nice and snug and you probably can't ever get it out so if you mess up just throw it away and you only lost about 10 cents.
Tie a bunch together with ribbon or put into a mug as a gift.