@Raksha2 There's really no such thing as an "Airbnb property" for sale. Airbnb listings can't be transferred to a new owner- you would have to set up a new listing in your name. And if a house seller tells you that you can easily just transfer the Airbnb listing, they're either mis-informed or lying.
So just look for a place that's for sale that you think would be good for an Airbnb and set up your own listing.