95% of airdrops I did were worth like 1$ or less. But the other 5%, some of them were worth more than 50$. Byteball, Helbiz and some more were quite impressive.
I'd say if you have time and choose projects you think are great, you have great chances of making good free money with less effort.
i seem to have to reconsider my airdrop strategy. so far i have not got token through an airdrop. but apparently there are really airdrops that are worthwhile. i hope i find such an airdrop. will definitely take part again in a few airdrops.