Yeah, that sounds about right. The box of 100 pcs was 22.xx at HomeDepot. Do you recall if yours was a brighter/ultra/artic/whiter than white(lol), white color?
I took a closer look at it and it isnt white-white. If you want to go with a pure white, you are probably going to have to get it special order or from a tile shop, however then its going to be around $50 a case.
Great work... the subway tiles in the bathroom... those 3"x6"? Also, what size spacers did you use for the grout lines? I'm about to do the same basic design in my shower surround and debating 1/16" and 1/8"..