How to acces blueprint variables before spawning or functions

So how to acces a variable from a blueprint or a function before spawning,

instance we need to build a building but before building it we need to know the Price of it, how do i do it?

Sort of sounds like you need to separate out that information into an external blueprint that has a struct containing an array of this information about the buildings, cost, blueprint class to use, Etc. That way you don’t need to insurance the class to look at which is a fairly slow way of doing it.

You could get class defaults which will return the default values of a class variables

So in a simple sentence UE4 can’t, make you be able to acces blueprint values before spawning the blueprint ? what about c++?