Hate being lied too

So my bf asks me for money saying it's for "food, and cigarettes" so I gladly give him some money he doesn't get paid till Thursday. But come to find out he just goes out and buys weed with the money I give him... like today. I'm not stupid. He said he was going to get cigarettes and his gram took him ans he forgot his phone at home and she called him 9 times it doesn't take long to buy a pack of cigarettes so I already knew from that, that he lied. Like he can't be truthful with it. It's stupid