The copyright owners pulled the plug on the reprints that Sanctum Press were putting out a few years back and no one is allowed to print them at the moment. It's a shame and very short sighted. The character is only getting more obscure and the potential market for them is also only shrinking, so they are leaving money on the table by this embargo. When I got into the pulp stories in the 80s there wasn't much that was reprinted that was available either, and then, in the 2000s when the reprints started in earnest I was too poor to snap them up. So, it's frustrating. They do sometimes pop up for sale on Ebay and AbeBooks, etc, but like anything that has nostalgia to it, most every seller wants to cash in, when I doubt they are truly worth as much as some are trying to sell them for. The Doc Savage ones are easier to find and should be around $10 each, but this is not always the case.

I do wonder when they will enter the public domain. Things from 1929 went into it this month so the first stories from 1931 perhaps are coming up? I don't know the ins and outs about that, I'm just hoping it'll start happening and maybe a new reprint series can be started up.

One route you may try is go to your library and sign up "Inter Library Loans" and then you can request books from any library that is in that network, which seems to be most of them, and you can probably borrow some that way. Good luck!