I was buying 10 cameras so any savings is multiplied x10.
I learned the hard way that there are Chinese and "International" (English) as they described it, cameras.
Specifically the DS-2CD2232-I5 (EXIR Bullet) there are two, and the difference is visual.
The US/International one has an integrated camera mount on the back.
The Chinese version does not have a camera mount. You use a standard 3rd party camera mount with them.
So if you're getting the DS-2CD2232-I5, make sure it's the type with camera mount (they cost $10-20 more). You can tell from the photos.