My suggestion to you is: bring some special local products from where you went to school. I believe your parents will feel very happy because they know that you are a very thoughtful child.
In fact, what gift you give is not the most important thing. The most important thing is that you have this filial piety. Parents will not ask you to give them anything, or how good the gift is, but parents can feel your heart.
Of course, if you can cook, you can buy some meat, fish, shrimp, etc., go back and cook for mom and dad, and then the family will eat and chat happily. I believe that the atmosphere is very beautiful. I believe your parents will feel very happy because they can eat the food cooked by their own children. I think this gift is the best gift, and it is economical and shows sincerity.