How to become fit?

Hey everyone )) Well I am 20 years old (5.74 inches and 147.4 pounds), I am mainly a pear-shaped, with very small breasts, and good ass. In all my body is good, but I am not exercising enough, I can say for the past year, I didn't. I am living in france now and I am student, so I don't really have much money to go to any gyms or any of that, plus I am really lazy :$ I am stretching almost everyday, but I need to have a firm body, What should I do, without having to pay lot of expenses
How to become fit?
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