Bitcoin faucets are sites that give out a small amount of Bitcoin (aka Satoshi) for free every few minutes. Because these sites are basically giving away free money, they have become extremely popular.
Faucets were originally created to spread the adoption of bitcoin across the internet. The original Bitcoin faucet was made by then- Bitcoin Core developer Gavin Andresen, and believe it or not, it used to give out as much as 5 bitcoins to each user!
Since then, cranes have become more business-oriented. Today, faucets are sites that give away small amounts of bitcoin to users every few minutes, earning money by showing ads to those users. As long as the site owner earns more money from advertising than the amount that he distributes to his users, the faucet remains profitable.
Most faucets either pay directly to your bitcoin wallet or use a third party micropayment wallet like Faucetpay . While this may seem like a hassle at first glance, it’s actually very convenient as all of your payouts are concentrated on one or two sites. This makes it much easier to withdraw and track your money.
That being said, be aware that since the faucet industry is notoriously a bit shady, things can change relatively quickly. So be sure to read the terms and conditions of each faucet you use. Here are the main things you should pay attention to first of all:
Payout amount – how many Satoshi do you get for one issue?
Timer –  how long is the interval between outputs?
Minimum Withdrawal – What is the minimum amount you can withdraw from a faucet to your wallet?
Withdrawal method  – are payments made directly or through a micropayment wallet?
Referral fee – how much do you get paid for referring new users to the faucet?
And most importantly: the minimum amount of replenishment! – what is the minimum amount of replenishment (deposit) set for your cryptocurrency wallet to which you withdraw your earnings from the faucet?
Remember! If you try to replenish your wallet with an amount less than the minimum for replenishment, your money will simply evaporate!
There are wallets that do not set a minimum replenishment amount, for example, the same  Faucetpay or  freebitco.in

And finally, the best Bitcoin faucets I know so far: 

And yes! Please note that payout amounts may vary depending on the current cryptocurrency exchange rate.