How can i lose 10-15pounds in at most a month?

Im going to be 18 in a couple of months. Im 120 pounds and 5’4. I have really big thighs. When i sit down i have a stomach roll and i have stretch marks and cellulite. I want to lose about ten pounds in the next month maybe even fifteen. My ques is how can i do this? Its freezing outside and i cant afford a gym membership. Please help i have a terrible body for my age. Btw im a girl.