In the US the most popular way to get bitcoin is from a bitcoin exchange called
Coinbase (
www.coinbase.com). Another popular option is
Circle (
www.circle.com). There is a site called
Local Bitcoins (
localbitcoins.com) that enables you to buy bitcoin either online or in person. If you need help buying bitcoin, consider asking the community for help. The people in the
Bitcoin Subreddit on reddit always have suggestions to help new people get in to bitcoin. Please always use discretion in all concerns regarding money. If it sounds too good to be true, it probably is.