I received a lot of tokens from Airdrops, but they haven't any value yet. When will be this tokens got value? in USD I mean?
Some of them may have a value in the future but some of them may not. Don't hope too much from airdrop as you get them for free and you should not join all available airdrops out there. Do some researches on the project first, if you think it will be good project then you may claim it and leave it if you think it is not good project.
Forcing yourself to join all airdrops will a little bit wasting your time because nowadays airdrops requires you to do many tasks. I cant find a pure airdrop these days, most of them should be called as telegram bounty, social media bounty etc.