You get a voicemail from somebody claiming to be a journalist, either from a radio station, newspaper or TV. He says they would like to do an interview with you about a specific subject – it might be business, sports, local events, etc.
He might say he came across your info online and thought you would be a good person to interview. Happy to answer his questions, since you might get some free advertising, you call the number provided. That number is registered as a premium number, so you end waiting in line for several minutes, while your phone bill records an extra $20 a minute.
How to avoid: any reputable journalist has a voicemail; so if you can’t leave a message right away and have to wait in line, just hang up.