If you’re a teacher, you know that each year, you’re going to be required to buy a ton of things for your classroom—anything from school supplies to educational decorations and books.

School shopping is just something many teachers do in their career. In fact, more often than not, their districts don’t cover the cost of supplies such as these.

One math teacher at Lincoln High School in Des Moines, Leland Michael, is well aware of that fact. But he doesn’t mind, as most teachers don’t, because to be a teacher means you value education.

But during one shopping trip, something got to him. He had two different sets of parents approach him in the school supplies aisle at Walmart to complain about all the money they needed to spend on supplies.

“This is just ridiculous,” they told him. “I don’t know how these teachers think we are suppose to get all this stuff.”

Little did they know that Leland was one of those teachers. They figured since his cart was full of supplies that he must be a parent too. Many parents don’t realize how many things a teacher needs to buy for a school year.

“As they complained, they seemed to be oblivious to the fact that my cart was filled with a class set of all the supplies they were buying—which should have been a pretty clear indication that I was one of those greedy teachers they were complaining about,” Leland wrote on his now viral Facebook post.

Leland didn’t let it get to him too much and went on his way. And when he was checking out, his day took a much better—and unexpected—turn. A man in front of Leland checking out with his own school supplied turned around and asked Leland if he was a teacher.

“I just want to thank you for everything you do,” the man said to Leland. “I see your cart is full with supplies, and I just wanted to help out as much as I can.” He then handed Leland a $25 Walmart gift card as a thank you for all he does.

Of course Leland was blown away by this man’s generosity, but something else really struck him about his two different encounters he had this day.

“The kids who heard their parents complaining heard this message: ‘School is not important enough to spend money on it, teachers are not to be trusted and have bad judgement, and learning does not require investment,” Leland wrote. “The kid whose dad handed me the gift card heard: ‘School is important enough that we should give more than required to make sure it is successful, teachers should be respected and valued, and learning requires us giving it everything we have.’”

Leland is hardly saying that he thinks all parents need to spend tons of money on school supplies. In fact, he sympathizes with parents who aren’t able to do that. But he does want to acknowledge that there are teachers who will likely be able to help out that child.

“If money is tight, and you struggle to buy your child school supplies, I understand. Don’t worry: more than likely your child will have a teacher and a school that makes sure they have the supplies they need to be successful this year,” Leland wrote.

He just asks that you send the right message to your children. “The man who gave me the gift card not only made my day, but I also know that his daughter will enter the classroom this year with a very different perspective about her teacher and her education, and that is extremely powerful!” he wrote.

Wen you go school supplies shopping with your child, think about what kind of message are you sending your child. How much money do you spend on school supplies in a year?