My brother purchased a digital camera at Walmart that required a Windows driver. It did not use removable cards. It simply did not work with the Mac. I have used a VistaQuest VQ1005 keychain camera. This camera cost $5.00--you know, the bill with Abraham Lincoln's picture on the front. This keychain camera works perfectly with
iPhoto and supports USB Automount even with the battery removed. It used standard SD cards.
VistaQuest no longer offers $5.00 cameras, but it does offer cameras at much less than the $75.00 mentioned above. You may research its product line
here. Please download and read the product manuals before making a decision.
Nextag® offers a wide variety of keychain cameras at various price points. You might want to check-out them as well.