Anyone here concentrates in buying/selling empty land

Im located in Phx,Az and its common here to still see empty dirt land in prime areas of city, as an example, my father who knows next to nothing about real estate purchased a 7k sqft gated dirt land  in the city 3yrs ago for $35k cash, was planning to invest in it but it was too much hassle for him so recently he sold it for $140k .

What's a good way to find good deals on empty dirt land  in the city or close by, does mls offer this search option. Im guessing this option does better with cash at hand than getting a loan.