Little-known fact: "All Hass avocado trees have been grown from seeds (or were grafted from the cuttings) of a single tree which was grown from a seed purchased in 1926 from A. R. Rideout of Whittier, California."
My best friend lives in Whittier and I once saw the original tree. My friend's wife's family have a house with 2 HUGE avocado trees. He'll let visitors cart away a bushel of the delicious fruit if they ask.
Large, ripe Hass avocados typically sell for about a dollar. The price fluctuates a bit depending on the supply. Stores in California typically have massive avocado displays, while the rest of the country has fewer to choose from.