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Coinbase is a good place to buy Bitcoin, Ethereum, Litecoin, and just as of today Bitcoin Cash.

Be ready as it will take several days to verify your identification and later your funding bank account if you are not paying with another cryptocurrency. Do your research on the coins available to you. Good luck.

Coinbase seems to be the simpliest option. Fees are reasonable and the wallet is pretty good. That being said why so little, $20 might grow to $50 or even $100 if your really lucky over the next couple years, but that's nothing in terms of actual USD profit, I would suggest trying to find at least $50 at minimum ideally around $100 if you want to see any substantial profit. But if you just want to learn how the system works and aren't serious about investing then you can go ahead and just buy it on coinbase,

Alright. Thank you :)

Most places won't give you the time of day unless you can invest $1000 or more. This is mainly due to the transaction fees. So if you're looking for a cryptocurrency to invest in, consider some of the alternatives. While you might not be able to invest $20, you might be able to get away with $50. You may need to wait a bit to see a return on investment, but if it works, it works...