Google has promised to return at least $19m (£11.6m) to parents who were unexpectedly billed for in-app purchases made by their kids.

The web giant today agreed to the payout in a settlement with the US Federal Trade Commission. According to the watchdog, children could to go on spending sprees with mummy or daddy's credit card via the Android Play store, buying up game power-ups and other virtual gumble.

As a result, at a minimum $19m will be repaid to punters who didn't explicitly authorize the payments.

"For millions of American families, smartphones and tablets have become a part of their daily lives," said FTC Chairwoman Edith Ramirez. "As more Americans embrace mobile technology, it's vital to remind companies that time-tested consumer protections still apply, including that consumers should not be charged for purchases they did not authorize."

The FTC found that when Google started allowing in-app purchasing in 2011, there was nothing to stop kids running up large bills for new software and stuff like virtual currencies.

A year later Google added a consent form that the cardholder had to click on, but it didn't mention that the form gave tearaways a 30-minute buying window before they would have to pester their parents for permission again. This allowed children to buy more stuff than their parents expected.

"We've already made product changes to ensure people have the best Google Play experience possible," the firm told El Reg in a statement. "We're glad to put this matter behind us so we can focus on creating more ways for people to enjoy all the entertainment they love."

Apple, meanwhile, agreed in January to pay back $32.5m for allowing the same sort of in-app spending sprees via its online shop. After paying up, and altering the App Store payment systems, Apple reportedly suggested to the FTC that it take a look at Google and others over their policies.

Google's settlement now means the FTC will be taking a long, hard look at Amazon and its in-app purchasing systems. So far Bezos & Co. has refused to settle with the FTC, saying that instead the firm plans to fight its corner in court.

The FTC isn't the only agency taking a stand on the amount of money kids are spending online without their parents' consent. A month after the Apple-FTC settlement, the EU said it was investigating Google, Apple and the games industry's role in in-app spending, and while Google has won praise from the investigators for trying to sort out the problem, Apple appears to be less keen to stop the practice. ®