I've joined the airdrop over the past 3 months and I only get very little value from the airdrop, the majority of which I have to keep it to add value.
So how can I earn a few hundred dollars a month if the bounty is a good plan?

Airdrop and bounty campaigns are good source of extra income as long as you are hardworking and atleast you have a high rank account, cause the higher the account you have the bigger reward you will get.