You won't need a visa, you can apply for an Esta. But, Esta only allows visits up to 90 days. I strongly recommend that you apply for an Esta instead of applying for a visa. Are you a citizen?
Let's say you choose to apply for a B visa anyway: the most important thing about getting a visitor visa approved, is showing strong ties like a job, house, etc. to your home country. This way, they don't have to worry about you trying to stay in the US. Being able to visit for 6 months doesn't show very strong ties to your home country. And, you will lose your Esta privilege if your B visa gets denied.
You can apply for an Esta here: https://esta.cbp.dhs.gov/