I purchased one of the 5mega pixel type for about $75in the USA a few years ago. All I wanted it to do was scan old 35mm slides before they turned to dust. It ran from the usb port, and admittedly you had to load them one at a time.
However it was easy enough to sit in an armchair with laptop and scanner on a table beside me and run a production line that allowed me to eventually scan over 2500 slides.
The end result was perfectly good enough to view full size on a computer screen. Okay maybe not HD quality but for saving old family pictures more than good enough.
It also scanned colour negatives very well.