I will also suggest airdrops to be the way of earning free crypto without investment but you can’t just be too certain about which one will pay you and which one won’t since their are lot of scam, you never can tell which one is worth your time.
i don't fancy just chasing after airdrops just because you are hoping to earn some free crypto and then while away your time on project that might or might not eventually yield the best of returns. airdrop is good and for a beginner, it could be a good way of earning some tokens just so you can adapt well in the crypto community but it is never to be seen as a method that should be used in the long run for earning crypto. it is best to see crypto as money and if that's the case, it becomes clear that there is nothing like free money or free crypto, you have to work and earn your money rather waiting for free things. even regarding airdrops, the amount of effort you need to put into performing all the task is not too simple and hence the reward gotten from airdrop hunting is not a free crypto.
For beginner who is looking for the best easy and free way to earn airdrop have been the best I mean among the top recommended even as their is no free money anywhere at least some airdrops gives out peanut after taking a whole lot of your time where they are asking you to do some random task for them. If the person have earned freely from airdrop and want to expand more that’s where they can work and start earning real something either by advertising and promoting their skills online where they can hire them and pay them with crypto.