Make a creative coupon describing the free goods or services. We were able to come up with plenty of gifts in this price range. Help your friends save their memories. Give them a blank album or one already filled with pictures and mementos. Stores like Hallmark and Staples have a good variety of relatively inexpensive albums.
Most stores offer gift certificates of varying denominations.
Buy them an assortment of products. A gift most teens would love to receive. Give money to the local Humane Society in your friend's name. Donate money or gifts to a homeless shelter or Santa Fund under your friend's name. Buy or make unique beaded jewelry for your friends.