You are not participating in IEO or public sale so I wonder why you would think of sending your ETH in exchange for a token, an Airdrop token for that matter, which probably might not be listed nor have any value nor any good thing to offer at all. This is a cheap scam, therefore don't send any ETH rather delete the message because it won't end well. Good airdrops don't require your Eth rather it requires you carrying out some tasks after which you are sent the Airdrop token, so any airdrop asking for payment before sending the token is a scam.