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 or use code tags so it becomes non-clickable.