How do you not spend money?

I'm having a hard time not spending money (even small purchases.) Once I get my paycheck on Wednesday I'm scrounging around by Thursday. I never buy anything big, it's just little things here and there. I make about $3500 a month and I have about $1100 expenses. I'm going crazy with not knowing where all my money is going. I don't have any subscription type services nor any credit cards. I'm just wondering how people don't just spend.