how to get a house in fallout new vegas?

Yes, you can get a house in Fallout: New Vegas, but no, they are not anything like the houses in Fallout 3 in that only one gives you the ability to buy upgrades, and those upgrades are lame, as in buying a dresser for 300 caps lame, and no chem lab or med lab, and the others have nothing like that unless you consider the one that has a live-in repairman who charges you caps to repair anything.

Yes, there are half a dozen or more, but you have to earn them by earning the affinity of the faction to which it belongs, e.g. NCR, BOS, etc, after which you'll be given the key and sometimes the location (others are bugged and you have to search for them.)

Yes, you can live in any or all of them or anywhere you want.

BTW, as I'm on PC and a modder I made my own house with all the amenities and plenty of storage in Goodsprings right next door to Doc Mitchell in fact.

Hey down there, there's also a Follower's Safe House.

Casino Suites:

Lucky 38 Presidential Suite:

You'll get this house when you agree to help Mr. House

The Tops Suite:

You'll get this house after you talk privately with Benny

Safe Houses:

BoS Safe House:

You'll get this house by doing quests for Elder McNamara

NCR Safe House:

You'll get this house by doing quests for President Kimball

Caesar's Legion Safe house:

You'll get this house by doing quests for Caesar