The city is mulling a plan to make some extra money by charging tourists to take the Staten Island Ferry.

Right now, the boat ride is free for all who want to ride.

The mayor says charging out-of-towners has been considered before, but it comes with complications.

Among them is how to implement a fee for tourists without charging residents, and the cost of building and maintaining a fare-collection system.

Still, the mayor and some tourists agree the fee could be a big help for the city. 

"I certainly would prefer to have the revenue while making sure nothing that we do changes the sanctity of it being free for New Yorkers," said Mayor Bill de Blasio.

"I look for free, so if you're going to charge me, I probably won't be on it. So you're not going to, it's not going to help me," said one tourist.

"I don't think it's a problem. Because all the other ferries, you have to pay for them," said another.

"New York City could use the funds, and we pay for everything else anyway," said a third.

The mayor says he will ask the budget office to look into the idea.