Pimples!! Argh 🤬

So I am 13 years old and have really bad acne especially when I’m on my period. The thing is I really want to get rid of them because I just got to high school and feel really self conscious about them but I also don’t want to be spending a bunch of money on products that doesn’t work or even make them worse. My friends have asked me about my pimples and I try to act cool about it like it’s not bothering me but it really is. I was wondering if anybody has any tips on getting rid of pimples with out spending loads of money?