Yes, the O scale does cost! But, for now, it's the only game in town so the other choice is to scratch build. It could be done, but it would take at least as much money and years of time. I'm working on my second loco (same number but will be weathered) and I have two coaches in various stages of prep. I also have a couple of the HO scale locos and one HO coach that I added a full interior and passengers to.
I've spent the better part of twenty years photographing there, I really like the old steamers. Had a chance to ride in the cab and took it!! It was loud, hot, dirty and shook like an industrial sized paint shaker!