Why does he keep asking me for money if he know I don't have it?

ok so me and this guy have been talking for a few months. he hit a financial hole and I was able to help him out a few times. lately he hasn't tried to see me and when he does call its to ask about some money. we've got into an argument a few times over this money. he hasn't made time to see me but he expects me to give him some money. I didn't have it yesterday, the day before or the day before that so what makes him think I have money? I didn't call him in like 3 days, he ended up calling me once again asking for money. I know he can tell I'm irritated now, I'm no longer that nice girl he used to know that would do anything for him but I'm just like wtf what is his deal? is there something I'm not getting here? so do you think acting mean towards him is gonna help? how should I approach the situation?