What kind of airdrop which itself asks to buy a coin ... it's funny .. it seems like a scam, it's not known at which round of airdrop the developer will run away with money .. Stop fooling people. otherwise soon be in the prison .. this is my advice to you ..
Everyone is entitled to his/her opinion. However, I would advice you do proper research as to why most airdrop project fail and very few succeed. This strategy that you are condemning is part & key of what succeeded DO.
Can i join in Airdrop Cosmos? but i don't have 750 cosmos coin
You can join and its still early to join. You will have to go buy at least 750 CMOS from any of the exchanger its listed on, that shouldn't break your pocket (because its far less than 20$).