For those of you looking for a cheap pair of birkies, matchesfashion has them cheap, particularly if you are buying a few. I picked a few for me and my missus. Have bought from them before at their last sale on Birkenstocks (they're authentic).
Edit: Also use an international transaction fee free card (I used my ING) to avoid currency fees
Mens Arizona: Black and Blue - $47.70 (after code Extra10)
https://www.matchesfashion.com/au/products/Birkenstock-Arizo… sizes EU40 - EU44
https://www.matchesfashion.com/au/products/Birkenstock-Arizo… sizes EU44
Mens Arizona: Brown Smooth Leather - $57.70 (after code Extra10) sizes EU40 - EU41
https://www.matchesfashion.com/au/products/Birkenstock-Arizo…
Mens Arizona: Brown Suede Leather - $57.70 (after code Extra10) sizes EU44 - EU46
https://www.matchesfashion.com/au/products/Birkenstock-Arizo…
Also have the Mens Ramses faux leather black - $42.30 (after code Extra10) sizes EU39 - EU46 (except EU40)
https://www.matchesfashion.com/au/products/Birkenstock-Ramse…
Just out of interest are the sizes weird? Are these mens?
39 is the smallest available and I thought that was a pretty common ladies size.