As others have mentioned, that is after the property has sold. If you are looking to buy a house, that information is not going to help you. However, even for sold information, depending on the county you are in, those public records aren't always accurate. I don't know how frequent that is, but I suggested using public records when we lost access to MLS data a few years ago, and a coworker said they had problems with that data from some counties in the past.

If you are buying a house, the MLS is the place you need to go. And that is mediated by a Realtor or Broker in most cases.

Those are completed transactions, not properties listed for sale.

there's usually a 30-60 day delay on the public records. MLS gets that info in a day or two, if not hours, usually from the listing agent/brokerage iirc.

Purchase price is not public in all states

It isn't? What states don't put that information in the property tax records?

Montana for another. There have been attempts to change that which have all failed in the face of industry lobbying and (more importantly) a Republican controlled legislature

In Texas I was able to lookup the original mortgage amount on a house, but not the actual purchase price.

Texas for one. No duty by either buyer or seller to report the sale price.

That's not useful to someone looking to buy. Listing data is held exclusively by the MLS.