Spend it or save it?

I have a part-time job since this semester, which is Eve and Fiona recommended me to interview with a cram school teacher. After I get the job, I have seven hundred dollars a week. My parents told me to save the money I earned; however, I just cannot do it! I desperately want to save money for future using but somehow I always spent all of them on something that I couldn’t remember now. It’s kind of ambivalence, when I bought things, I thought it’s necessary at that moment. However, when I saw the empty envelope, I felt sorry about it. I don’t know what to do especially now my two envelopes are empty; it means 5200 were gone in two months. Ellie said I should limit the expense I cost in 100 every day. Well, one thought flashed my mind was “poor like a beggar again!” However, I agreed with her. I really spent too much money these days and I have to make some changes or I will become a real beggar one day. I think I’d better learn how to manage my money or I will regret when the third envelope is gone again.