What should a boyfriend send in a care package?

My girlfriend and I are separated during the summer (we're in college together) and she recently sent me a care package with a nice note and a tub of cookies. As we'd only been dating for a month before summer, it was unexpected and very sweet. I'd like to send something back- should I send a care package back? If so, what should I put in it? If not a care package, should I send her something else, like flowers?