I am also
very interested in steam. But I absolutely don't have the budget for it anymore. I have the Midwest tiny single oscilator I built as a kit many years ago. I currently have the Midwest Heritage engine. That is the limit of my budget for steam anymore.
That said, I bought a book last year titled
Making Simple Model Steam Engines by Stan Bray. It is a DIY manual on making steam engines with hand tools and more complex steam engines using simple hobby lathes. I am just now reading it and it looks like I will be able to make my own steam engines in the future and that is pretty exciting to me!
BOOK