HTC confirmed that there are two One M9 variants: one with 32 GB, and one with 64 GB of internal memory. In Taiwan, the M9 32 GB will cost 21,900 TWD (around $693), while the 64 GB model will be sold for 23,900 TWD (about $756). As you can see, the price difference between the two variants is of only $63.
Unfortunately, it's not clear if both the 32 GB and 64 GB versions of the One M9 will be available globally. In any case, both have microSD card support, so storage space shouldn't be a problem.
Running Android 5.0 Lollipop with Sense 7 UI, the One M9 is powered by an octa-core Snapdragon 810 processor, and features a 5-inch 1080p display, 20 MP rear camera, 3 GB of RAM, and a 2840 mAh battery. You'll find out more about the handset by checking out our HTC One M9 hands on.
HTC One M9
source: ePrice (translated)