As a Midwest option for you, I use Jake Sweeney Mazda in Cincinnati OH for oem parts. Convenient online ordering and free pickup (since its local to me.)
I got a Mazda OEM engine filter off Amazon recently for $20.86 US + tax with free Prime shipping. Also a Bosch 6080C HEPA cabin filter off Amazon for $13.14 US + tax, again with free shipping.