I haven't get big income by airdrops. I think it depens a lot on luck, and the percentage of chance is very small. It would be better to spend time and chance on finding good bounty campaigns. They can bring a much larger income
The best airdrops I know was Polymath and Ontology. I sold 250 Poly for 0,4 ETH, that was cool. But Ontology airdrop was increadible. People could get from 1 to 8 ETH in ONT.
