As I recall there was a chap by the name of "Gizmo" who posted an article in 'the other O gauge magazine'. He had a nifty plan for making your own rivet press. I followed his plan, made my own, works dandy! I doubt there's more than $10 of material in the whole thing....even less if your workshop is filled with scrap this-and-that like mine was....is....always will be.
Update: I just found an archive of authors/articles for O Scale magazine... The author was John Gizzi. The article was from issue #45, page 38. You can download the pdf file for that issue/article by going to the O Scale website.
KD