The tried and true way of saving spots with a chair may become a thing of the past, as Canton resident Eric Meyer has come up with a more innovative way to ensure residents a parking spot. After facing several parking woes himself (including tickets and an eventual boot), Meyer developed Haystack, an iOS and Android app that allows neighbors to alert each other to open spots. The catch? Spot takers pay $3 and spot leavers earn $2.25, putting a price on public parking.

“I don’t see Haystack as buying a spot,” says Meyer, 24. “It’s an exchange of information. It’s an option for users to pay $3 to save 40 minutes of their time circling for parking.”

The concept of Haystack is simple: Based on GPS, residents can see and match up with others in their neighborhood who are either looking for or leaving a parking spot. (The app has users input vehicle type, so it can even match like-sized vehicles.)

Since its launch at the end of May, Haystack has acquired thousands of users, some of whom, like Canton resident Rebecca Moschina, are big fans. “I have used it about five times in a month,” says Moschina. “It’s always been a quick, easy exchange.”

But the app has also drawn criticism, mainly for its monetization of public parking, as well as potential glitches like people “squatting” in spots for a profit.

“I imagine the city will get involved the same way San Francisco has gotten involved in similar parking apps,” says Mike Brenner, CEO and cofounder of tech incubator Betamore. “My prediction is they’ll pivot their product into something different but related,” like another transportation app.

For now, though, Haystack is helping users like Moschina during desperate times. “Of course, nobody wants to pay for parking,” she says. “But I use Haystack as a last resort."