You do not have to pay to enter a sweepstakes or collect a prize. If you're asked to pay, the sweepstakes is a scam.
Be wary of  news that you've just won a sweepstakes that you never entered. It may be part of a nationwide sweepstakes scam and it could end up costing you big money.
How to spot a sweepstakes scam.
Part I: The answers to your most frequent questions; Part II: Sentences and statements that identify a lottery scam letter; Part III: It is illegal for US Citizens to enter foreign lotteries: Federal Statute