Are you seriously looking to BUY or just looking for data?
Hiering a Realtor, is the best option to buy a lot or land.
Data can be purshased from the TAR report.
Allen Tate Wake Forest Realty
Your best bet is to get a local agent to help you out in the search. They will be able to pull up everything on the MLS that is for sale and then be able to go back and do the closed lots to give you an idea of what land is selling for in each area.
As stated below, it does not cost you anything and you do get professional representation.
My web site is below and you can do searches on it.