re: Been following a vacant lot near me and I'm a little skeptical about the price drops

You didn't give much information but I'd start here.

Call the realtor to get the story then call a different realtor to get that story. Meet the realtor/s at the property and stay there a while, try to go around 5-6 so people can see you there. Go back the next day same time you were there and saw people then talk to them about the lot.
And/or. Just go investigate, hit the courthouse and look thru the details/look for easements/liens/ past liens. Check the obvious like floodzone, insurance rates in the area, cost to get utilities to the home, crime, property tax, and especially make sure it wasn't an old dump or other things that could be a problem.

That last lot might be the dump for the contractor when he built all of his houses. Talk to the old homeowners, they might know.