Most petshops, Craigslist, there are bunnies for sale every year at the county fair (here anyway. But I'm in PA) or see if there are any notices at your feed store (ours has a guy who's selling quail, and an ad for goats wanted, and someone who wants an old horse trailer to make a chicken coop out of, etc.)
And yes, you can keep just one. When I was a kid, we had a houserabbit for a while (only inside animal we've ever had.) He loved coffee, pepperoni, popcorn, and sliding across the linoleum. Sadly, he also enjoyed eating the wall, so outside he went.