Scammers have found another way to trick you out of your money.

This time they’re trying to get you to use that handy peer-to-peer mobile payment app that you’ve probably used to transfer money to family or friends or to pay for your share of a bill, but instead of using it to safely pay someone you know these strangers want you to pay them for a product you might find on craigslist or another online sales website.

The fraudster will make it sound simple – just use your P2P app and an email address or telephone number they give you to transfer the cash from your account to them and then they’ll send you the product. Only there is no product and there’s little chance you’ll ever see your money again.

While these mobile apps are great for paying people you know, they don’t yet have the same consumer protections against fraud that come with using credit or debit cards. Experts say to think of them a lot like cash: If you give money to the wrong person it’s likely that cash is gone for good.

Fraud.org offers a few tips for the best ways to use peer-to-peer payment apps.

The main advice is to use these mobile apps only to pay someone you know or trust – people like family members, friends, the babysitter or the person who always mows your lawn. Even then, you should make sure you don’t accidently type in the wrong email address or telephone number when sending the money, so it doesn’t go to the wrong person.

Don’t use your app to pay for products or services from people you don’t know. If someone makes this payment method a requirement for something like an online purchase, it’s probably a scam.

Bottom line: Use these apps for reimbursing people you trust, not for paying people you don’t know.