It depends on how close you are to your best friend in college for several years. Is it the best? It depends on my local income level, whether I hold a banquet in a hotel or at home and so on. According to my years of communication experience and living standard in Guangdong, I can give you a reference: 200- 1000 yuan. If you give gifts and red envelopes, you can send less. If your classmate is kind and knows the world, she won't accept it all. If there is anything else I can do to help the landlord, you can leave me a message at Baidu HI.