How many people are you talking about? If you are in a large chapter, you may want to make one big item as a gift to the sorority as a whole, and maybe make small gifts for your big, little, and others in your family. If you're in a small chapter, you are more likely to have the time/money to be able to give something to everyone.
If you cross stitch, there are things like hand towels and pot holders that you can buy, that have a little strip of aida cloth on which you can stitch, say, your sister's name and your sorority's flower. These are quick and easy to make, not too expensive, and very nice.
Hope this helps