A group of scammers are doing this and people keep falling prey of this scam where the scammers promise some big reward for doing something and then they "stop" the withdraw saying that you need to deposit some 0.01 BTC to get a reward - whose amount is much bigger than the 0.01BTC. That is their pitch, they try to incite the greed in you at that point. But as we know greed kills, just like speed.
Not that way I send bitcoins to the seller and they pay me cash in bank but the seller I trust requires minimum 0.01 to be sold. I have to basically withdraw my BTC at the end of the month.