PHOENIX (CBS5) -The Phoenix Police Department kicked off three weekends of “Groceries for Guns” on Saturday. It’s an opportunity for people to dispose of unwanted firearms and get a little something in return. Police told CBS 5 News more than 800 guns were dropped off at three different Phoenix locations in exchange for gift cards that can be used at Basha’s, Food City and AJ’s Fine Foods. Mayor Greg Stanton said Saturday’s event, the largest gun buy-back in state history, was such a “massive success” there might not be enough gift cards left to hold two more events planned for May 11 and 18. Phoenix police said they handed out about $80,000 worth of gift cards Saturday. So “Groceries for Guns” partner, Arizonans for Gun Safety, is urging the public to donate money to help pay for more gift cards. Those who participated in Saturday’s buy-back said it could be a life-saving program. “We need to get guns off the street – out of the hands of kids, young teenagers and irresponsible adults,” said Joe Alcala, of Phoenix, who dropped off a pistol. Bobbette LeBaron, of Mesa, feels the same way, telling CBS 5 News, “I had this gun that’s so – I’ve had it for 30 years, and I was afraid to ever shoot it again, because it’s dusty. So I thought, ‘why not trade it in?'” A $100,000 anonymous donation made Phoenix PD and Arizonans for Gun Safety’s “Groceries for Guns” program possible. People who exchange unloaded handguns, shotguns or rifles will get a $100 Basha’s gift card per gun. Those who turn in assault weapons will get a $200 gift card per gun. “It is anonymous,” said Phoenix police Sgt. Steve Martos about the buy-back process. “People are coming through, they’re driving through. They’re telling us where their weapon is. We are collecting that item.” From there, the guns are tagged and impounded. “Come Monday, some of our detectives from our gun squad will be going through the process of obtaining trace evidence from them, seeing if they were related to any kind of crime, then ultimately being destroyed,” said Martos. That’s something private buyers, who stood just outside of drop-off locations, tried to prevent by offering cash for guns. “It’s cheaper prices here than going into the store, because it’s so inflated right now,” said Darr Kadlubowski, who also told CBS 5 News one person actually gave him his gun for free. “I figured this would be a cheaper way to buy some guns and to save them from destruction.” Overall, private buyers didn’t have much luck. Most people who dropped off their guns said they want them destroyed – which Phoenix PD is glad to do. “If we prevent one person from being injured, one death or one crime from occurring we think it will be successful,” said Martos. Late last month, Gov. Jan Brewer signed a bill into law that bans the destruction of guns collected by law enforcement officers at gun buy-back events. It goes into effect in about 90 days, so police hope to have all of the guns collected this month processed and destroyed before then.