My recommendation is to start with an small amount. You can start with 0.1 BTC or less, which today is (still) less than thousand U.S. dollars. (You can use less money and buy a fraction if you prefer). The minimum to trade is $20.
If you are not having access to the BTC ATM machine than WesternUnion2BTC could be good way to have USD to BTC exchange at your neighbourhood. With Western Union is possible to exchange your cash for Bitcoins at your nearest Western Union point.
For converting cash into bitcoin, you need to open an account.
Opening account is instant and efficient. At the exchange there are efficient ways to conduct KYC (know your customer) diligence on you. They will do a standard verification to know who you are, and from where you are coming from. Once account opened, you are all set for buying Bitcoins for cash.
Good investing,