"how does one know what was sold and for how much?"
For example with domain names sales prices only a small amount of transactions are public. For example I've been doing it for 16 or 17 years and have never made any of my data public nor have people that I've consulted for.
Another example might be commercial rents. You can track asking rents but you can't really get a handle on actual rent paid since there are many deal factors (renovations, free rent, triple net etc.) that would change the numbers significantly.
For example with domain names sales prices only a small amount of transactions are public. For example I've been doing it for 16 or 17 years and have never made any of my data public nor have people that I've consulted for.
Another example might be commercial rents. You can track asking rents but you can't really get a handle on actual rent paid since there are many deal factors (renovations, free rent, triple net etc.) that would change the numbers significantly.