It is a scam (the "advance fee scam").

Learn how to handle scam/spam phone calls.
Visit this site to read more about it, and see how other 800notes posters solved their problems.
http://phonehelp.comuv.com/

I have had a man named Roy calling from this number saying we won money and a car. Wants $500

Showed up on my caller Id as cellphone JM so I called back and it was the same person that has been calling from an unknown number saying my grandma won a new car and $10,000,000,000 all she needs to do is send him $150