What bitcoin is really easy to purchase and sale to the any person in cash? If I purchase bitcoin and after a year I want to sale it with cash what I can sale it to any person? And for the same what I get cash or check?
There are millions of users of Bitcoin, who are interested in Bitcoin. If you want to sell your Bitcoin a year later, you will find a good buyer. When you want to sale it, maybe localbitcoins.com is a good choice. Millions of transactions are listed on this website. Buy some bitcoins, and then enjoy it. But first you need some knowledge about how to save your bitcoin by bitcoin-wallet. you can get started from here.

If you don't want use your own bitcoin-wallet, you can buy some bitcoin on a web exchange, like Poloniex or Bittrex, or you can choose a exchange by yourself, list of bitcoin-exchange.