I join airdrop for 2 months ago, and some of tokens i got were very low price on the market. I also get a bounty prize with much tokens (i think this half of ETH when i see from ICO price), but the token is still not in the market (maybe a scam) until now.
After one week I thought that airdrop didn't give me profit. Right now I only join the signature campaign.
Don't give up easily, there are still many ways to get coins if you believe in this crypto. My advice, you should to consider how much distribution of bounty tokens with participants in bounty campaign so you get more profit.