They might sound like something out of a cheesy '80s sci-fi blockbuster, but robocalls are for real -- and they're bad news.

If you've ever received a phone call from a recorded telemarketing message, you've probably been robocalled.  Common robocallers often claim that your auto warranty is about to expire or that they can help you reduce the interest rate on your credit card.  They'll try to sell you an extended auto warranty or interest-rate negotiation services.

But these calls aren't legitimate -- they're trying to lure you into a scam.  And if you take the bait, you could be out hundreds, or even thousands, of dollars.

The good news is that the Federal Trade Commission (FTC) is cracking down on these automated nuisances.  Businesses now must have your written permission before they can call you with prerecorded telemarketing messages, regardless of whether you already have a relationship with the business.

This rule doesn't apply to some recorded messages.  For example, informational messages still are legal -- like appointment reminders or prescription pick-up messages from your pharmacy.  Calls from political and charitable organizations also still are permitted, as are calls from financial institutions and telephone carriers you already do business with.

If you do encounter an unsolicited robocaller, never provide any personal or financial information.  That includes your Social Security number, credit card number, account numbers, driver's license number, and Vehicle Identification Number.

And if you receive recorded telemarketing calls but have not agreed to get them, the FTC wants to know about it.  File a complaint with the FTC at donotcall.gov or by phone at 888-382-1222.