The Expert's Panel

There is no magic answer. There is a reason why market data costs money. There are techniques you can use to try and extrapolate data from other known databases, but you will have variable results. However, to get meaningful hard data, in your niche, it costs money.

Paying the money for the right data can be extremely cost-effective because it can keep you from making costly or even fatal mistakes. Usually the cost of the data is 1% or less of what you can lose by screwing up when you don't have it.