Below is our shed and while yes, you could theoretically build the equivalent shed for half the cost (discounting your time and effort), but consider: The better versions of these types of structure that I purchased was made in a factory where jigs and forms are used to fit everything together, so the build is of very high quality. I understand the folks who make the board and batten sheds in PA do not make the vinyl or metal types of sheds which are made by other families.
Go to one of these places that sell these (scope out what’s in-stock first online) and make a close inspection of how they are built, the materials, etc. something like ours can easily have a roundwood lean to added onto the side to expand storage space. Another less expensive option might be to go with a Run-In style horse shed
and adapt that. Not having a floor might actually be better to allow for insulating, radiant heat, etc.