Don't send them anything, it's a scam!
No one will give you 0.5 btc for free. Even if it was my friend who did it then I'll have some doubts.
Besides why are they asking you to deposit 0.002 btc before you can withdraw? Why don't they cut it from the 0.5 then send you the remaining amount. It doesn't make any sense.
"If it's too good to be true.."
Please, remove the direct link to this scam website from OP or use code tags so it becomes non-clickable.
Yes, thank you all for confirming my doubts. I removed the link. Scammers shame!