How do I find the value of a vacant lot

[Steven McPherson]

I posted this on another board but I wanted to see if I could get some info from a builder's perspective as well...

I've got a buyer wanting to find some vacant lots in my area to build on. I'm planning to treat this like a wholesale transaction so that I get paid a finders fee. In valuing the vacant lot, do I use comps the same way that I would value a built property? What if there are no other vacants in the vicinity? Any advice? Thanks.