Now you might can find some newer made blanks from a reenactor. One guy I met at one made his own blanks(pretty much for every rifle or pistol used at a WWII reenactment) and everyone bought theirs from him. 300 for $25, I think
Long term use of blanks in any semi or full auto weapon will make it a smooth bore! This is because of the blank adapter which restricts the escape of burnt powder gasses. The more you shoot it rapid fire the quicker it chews out the rifling. I have an MG 42 bbl that I use with blanks and it looks like a shotgun barrel now. Took about 3 or 4 years. I also have a thompson that is getting close to that.
Anything more than 30¢ a rd for 30/06 is overpriced! You should be able to find factory blanks = US, Canadian or FN full draw - NEVER use FN head stamped M1909 blanks with a black wadding - they're made for MGs and will break your Garand.
There is a large group in Texas Called the Texas Military Historical Society. They have several GI units.