I received a call saying that I was approved for this government grant for $6,700. But he also told me that I have to buy a greendot money pack & $200 and give him my credit card number.. Give him the moneypack id of $200 And he would put the $6,700. Onto my credit card.

Things to believe:

* There ain't no such thing as a free lunch (TANSTAFL)
* If it looks too good to be true, it probably is.
* You have not won big bucks or a grant from the government   <<<<<<<<<<<<<<<<<<
* The tooth fairy really does not exist
* Everything you read on the internet is not necessarily true.
* It is illegal to pay money for a loan, BEFORE getting the loan!
* "Free Trips" are loaded with mandatory & costly extras, and you usually must give them your card number after listening to a loooong spiel at a hotel.
* Microsoft did NOT call you to fix your computer.
* The moon is not made of green cheese.
* The IRS will snailmail you, rather than phone you, if there is a problem.
* Jackalope milk is not an aphrodisiac.
* If you "green dot" or Western Union money to a scammer, the money is gone.

I also resived a call saying that I won federal grant of $6,000. But in order to get the money I was required to buy a greendot moneypak and pay $199.00. ??...

It's a scam.  You are NEVER required to pay money to receive a grant - ever.  You also cannot receive a grant you never applied for.

As per the Federal Grants website at http://www.grants.gov

YOU WILL NOT BE CONTACTED BY THE GOVERNMENT TO OFFER YOU A GRANT.
The government does not contact people to offer them money. If you do qualify for a government grant, the government does not request payment for it.

THERE ARE NO FEES ASSOCIATED WITH APPLYING FOR A GOVERNMENT GRANT.
Providing financial information to prove that you qualify for a government grant is typical, but you should never pay money to apply for a grant. People who run scams often claim to provide help and sometimes claim to be "federal government" officials, don't be fooled by these scams that request money from you.

ALL GOVERNMENT GRANTS INVOLVE AN APPLICATION PROCESS
If you have not submitted an application for a government grant and someone claims you have been awarded one, it's a scam. Grant money is not given over the phone for a fee. In order to qualify for a grant you must apply for the specific opportunity that you are qualified to apply for.

GOVERNMENT GRANTS ARE AWARDED FOR EXPLICIT OPPORTUNITIES
Government Grants are typically awarded to states, cities, educational institutions, nonprofits and other organizations to fund research and other projects.

GOVERNMENT GRANT APPLICATIONS AND INFORMATION IS FREE
Be cautious of offers that ask for your personal information (especially financial) when requesting a fee to access grant information. You can always access free information about government grants and other benefits at Grants.gov and Govbenefits.gov

If you get this call, please report it to:
http://www.grants.gov/web/grants/support/general-support/grant-fraud.html

First of all, you should read Slims, and Els, posts above. They're damn good.
Secondly, you DON'T win a government grant. You have to work hard to find them, they're usually not worth the effort & if you do qualify for one, the expense of the treatment for Carpal T. after filling out all the forms will make the whole procedure moot.
Third, even the U.S. government doesn't require payment up-front! That would be ILLEGAL!
Fourth, Only FRAUDS mention things like Green dot, Western Union, Vanilla, Pre-paid cards etc.
That should sum the issue up eh?
Be Safe. Be Aware.
Gunnar