If you're new to buying any type of crypto currency and you live within the US a good start would be to join Coinbase
(use the link below, we both benefit from the referral program)
https://www.coinbase.com/join/58a7ca890b120a0230929c50
Coinbase is the best way for the average individual to purchase or sell Bitcoin, Ethereum, and Litecoin with easy access. Once your account is created you can purchase with either your bank account, debit/credit card, or PayPal. A huge benefit from having Coinbase is that they are FDIC insured the same way your bank is making it a win/win situation for everyone.
If you want to look into Day trading you might want to consider having Poloniex or Bittrex. I strongly suggest to have both because Poloniex has higher volume and Bittrex has different coins that are not offered in Poloniex.
Once you get heavily invested into crypto currencies you will want to consider getting a hard wallet such as a Trezor or Nano S ledger to keep your private keys safe from outsiders.
https://trezor.io
https://www.ledgerwallet.com/products/ledger-nano-s
Please do your due diligence when it comes to investing your money and remember to never invest more than you are willing to lose. I don't see cryptocurriences going anywhere for a very long time but the market is very volatile so get ready for the ride.
If you have any questions or need any help please reach out to me!
"Best of Luck"