Opening a Bitcoin account and purchasing Bitcoin has a lot of restrictions. I believe this is part of the expanded efforts by the American government to detect and stop money laundering. You will have to provide substantial documentation of who you are for one of the commercial trading services.
I believe however, that if you run a full node, you can enter the Bitcoin system directly. Running Bitcoin core as a full node will download the entire Blockchain, including transactions, about 300G at this time.
The Rockitcoin ATM pictured is nearby the university. You can purchase Bitcoin for cash, after providing sufficient identification (your driver's license, a cell phone number). It can deposit to a "paper wallet". It first provides a slip of paper with the QR codes for a public-private key pair.
I was able to import the paper wallet at Bitcoin.com.
curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install > brew-install.rb ruby brew-install.rb brew tap ethereum/ethereum brew install ethereum
sudo apt-get install software-properties-common sudo add-apt-repository -y ppa:ethereum/ethereum sudo apt-get update sudo apt-get install ethereum
geth --rinkeby --syncmode "light"
geth --datadir=~/.rinkeby attach ipc:~/Library/Ethereum/rinkeby/geth.ipc console
personal.newAccount("password")
eth.accounts
eth.getBalance(eth.accounts[0])
author: burton rosenberg
created: 13 jan 2019
update: 13 jan 2019