Here's a corrected and improved version of your text:

My name is Alex. I live in Saint Petersburg. I don't have a big family. My mother's name is Natalya, and my father's name is Denis. My school is close to my house. School starts at 8:30 and ends at 3:20.

My mother gives me pocket money, but I set it aside and save up for a computer. I can fly quadcopters. I love spending time with my parents; we often watch films together. I communicate a lot with my friends, and I am interested in programming. I communicate freely with adults as well.

Let me know if you need any further help!