Problem buying ZP

I want to buy ZP just for the m4 jewelry, i'm gonna pay by paysafe but something confuses me. For 43$ i get 75.000 zp (with the bonus). And then i need 5.000 zp, in this case i buy for 9$ 15.000 zp. So the total amount of $ is: 52$. BUT the problem is paysafe comes in 10 , 25 , 50 , 75 and 100$. So i'm kinda confused on how to buy exactly 80.000 zp and not have to spend extra money. I don't want to buy a 75$ paysafe check (it's too expensive, and i'm a teenager). So how should i buy ?