1) On Sephora.com you can go to category (ie Fragrance) and sort by price. You'll then see about 10 different Sephora exclusives under 15 bucks. I love the Stella McCartney roll-on for your purse that costs $13.
2) Buy in packs - give individually. One for you. One for you. One for me!
3) Of course they also have their awesome Beauty Insider program that iSave explains here: CityBroke