Where did the dollar go???

So, this was our night this week. They boys begged to buy lunch. It was pizza day, usually they always take mainly because I am not sure I trust Zack with $$... Okay, we agreed to let them buy lunch after much discussion and explanation to Zack. $2.25 I manage to find. (I never carry cash). So they are excited as ever... that night I am doing the dishes, I see a yellow slip of paper from the lunch lady asking for a dollar. Zack owes $1.00 for lunch. I am now totally perplexed. Zack? Why do you owe the lunch lady a dollar?
"I don't know."
You don't know?
"Nope."
Zack, you had $2.25 for lunch where did the other dollar go? Is it in your jeans? Is it in your bag? go get them... Nope- not in the bag not in the jeans.. Another 20 min goes by.. 30 minutes total.
Okay.. I go to the kids school supplies and get out 2 dollars and 25 cents. Okay.. this might work.
Zack... where is the extra dollar?
"Will I still get into trouble if I tell the truth?"
Zack where is the other dollar?
He looks at me and says "I wanted to buy java juice after school. I wanted to try the lemon one. It wasn't that good, but I tried it. I used my dollar for that. "
???
Yeah.. Toby chimes in. "He didn't finish it, and Mr. Pete made him throw it away before we got on the bus."
So, you knew where the other dollar went and you didn't tell us? You heard us go through this for the last 30 minutes?? Blank look from oldest kid.. youngest kid thinking he is still in big trouble and isn't sure he should have told the truth.
"So, am I in trouble?"Zack asks...
What do you say? A five year old figured out to save his dollar so he could buy a juice he wanted to try and get pizza for lunch... In

my opinion that is pretty smart. How do you get angry at that?

No- I say. But next time, make sure you ask for an extra dollar if you want Java Juice. Okay?

"Thanks mom! So, can I buy again next wed??"

We are in trouble!! :)