There are many free ways to earn cryptocurrencies in the decentralized market. There are several affiliate programs, airdrops, or just by holding crypto coins in your wallet can help you earn indirectly without buying any token in actuality. There are multiple ways to earn free cryptocurrency without investment but they pay users into different Tokens (cryptocurrency) and you can either withdraw or exchange (to Bitcoin or any Altcoin) them and convert them into fiat currency such as USD through exchange