Damn! Any airdrop asking one to pay is scam. Also, I usually advise crypto enthusiasts, don't just click any random site you come across, some will even install spyware to your device. Some sites will ask noobs for private key or keystore, in a bid to hack their wallets. Let's be guided please.
Well, a strong antivirus will prevent them from installing unimportant files to your computer if you know how to tweak your own computer. For sure newbies will always gonna fall to that part when the site starts asking their private keys. Anyway, the best way to prevent it is to not click on an unknown site or any site that seems to be dodgy, you will know it eventually if you are a computer geek.