This month, the Orange County Museum of Art in Southern California is reopening, and it’s not charging any fee to enter.

Admission will be free for the next decade, thanks to a corporate donation. About a third of museums in the U.S. don’t actually charge anything, according to the American Alliance of Museums. And, there can be a financial advantage to that. 

Museums that don’t charge admission avoid some costs, because it takes money to actually – take money.

“There needs to be staff who are selling tickets, there needs to be software resources to help communicate the ticket arrangements and do the transactions,” said Michelle Moon, an independent consultant for museums.

It could mean getting more people in the door, too.

“One advantage of not charging admission is removing many of the barriers, not all of them to, to visiting a museum,” said Laura Lott, president and CEO of the American Alliance of Museums. “And getting a new and more diverse audience into the museum.”

Another advantage to not requiring people to spend money is they might end up, well, giving it to you. At the U.S.S. Constitution Museum located near the historic ship in Boston, there were quite a few visitors in the lobby on a recent afternoon. 

The museum used to charge $3 for adults and $1 for kids. Then in the late ’90s, it tried an experiment and got rid of the fee.

Museum president Anne Grimes Rand said the number of visitors tripled.

“With increased traffic, we saw donations and increased revenue in the store, which meant it was more profitable to stop charging admission,” Rand said.

Because if it’s free to get into a museum, people might be more likely to enter – and then spend that money on a postcard or a hat.