Stumped, need help getting my gf a gift?

Well my girlfriend is moving in about 2-3 months and im trying to spend most of my time with her, im saddened that she is moving but im accepting and we promised each other we would stay in touch and i would visit her every so often, im 17 shes 16, shes been one of the best girls iv ever dated, i want to get her something that'll always remember her the time she was with me. What do you think