Use a search term such as "real estate Alabama" to find some real estate agencies in the area that interests you. Most real estate agents sell lots and parcels as well as homes. You can calculate the average price of consistently sized lot, or the price per acre, this way. The prices will vary quite a bit depending where in Alabama you want to buy, so you will want to find a site that sells where you intend to buy. You will need to know about the land--zoning (residential, commercial, agricultural, etc.), if it is raw or improved (septic or sewer, water, electrical, etc.), and access (how do you get to it--roads, streets) in order to compare apples to apples. But if you are buying a home, not land on which to build a home, that's different. You would want to compare the home you are considering with similar homes (age, size, amenities) on similarly sized lots or parcels.
