Yeah it's cheaper in bulk KV.

There are a few DB service providers, Southcoast, Accuratings, RSB, VRC are the four I know best. I think TRB (website) do as well but slightly differently. The first 2 I mentioned cost about $4000 per year, I think RSB is more exe as is VRC (I think they're combined somehow).

The first two are well worth it, they also have an error rate in their data, but no data is totally clean. From them though you get all results, all fields and a ready made database in which to put it, or you can do like I do, use their results files to make your own DB. Sure quicker than getting it from websites.