I haven't reviewed the agreement you have to sign to receive the free version lately. I expect there is verbiage in there about not being able to use it for commercial work.
As Ken said, the education version files will not open in the commercial version.
Step files are dumb solids, they don't come with features, so expecting a company to pay you to provide a dumb solid model is highly unlikely that will work out. Also, drawings won't be correctly connected with the models during a conversion.
My opinion is that it you would be violating the agreement you signed to get the software and you wouldn't have any customers willing to pay for the "dumb solids".
