A so called "experiment" to have people pay to get into an otherwise free state park angered some people.
Red Rock Canyon State Park only charges for overnight campers, but on Easter Sunday is also charged a $4 per vehicle entrance fee.
"We have to come up with creative ways to fund the park," says Park Manager Dave Sutton.
Sutton says Red Rock Canyon operates at a $220,000 loss every year. On Easter Sunday, the extra cash generated from the entrance fees amounted to $1652.
"We are trying an experiment," says Sutton.
Park-goers told News 9 they believe the random charge wasn't fair to those who showed up on Easter Sunday.
"It's probably not a good idea that nobody knew about it," says park-goer Ray Murray. "They need a set of rules and they need to stick with them."
Sutton says the extra fee was an experiment to see people's willingness to pay to enjoy the park.
"The rules get bent a lot down here," says Park-goer Larry Lowry.
Sutton says he's trying to put out more notice next time he charges, but he doesn't know when that next time will come.
The Oklahoma Tourism and Recreation Department says State Parks managers have the statutory authority to charge entrance fees .
It adds that the fee is not a statewide campaign, but just one idea to start adding revenue.