The Symbol/Motorola/Zebra/whoever-owns-the-brand-this-month li2208 is cheap and can read a phone display. I think it can decode PDF417 (? The 2D barcode on the back of your driver's license) but Im not sure about QR
I think by default it handles pdf417 but you could enable a few other formats through configuration. QR seemed to be easily supported by even the cheapest models 6 or so years ago. It's like the scanner tech itself kinda stayed the same but what changed was the connectivity to the PC, moving from serial to serial-over-usb. At least that's what it looked like with the sample scanners I had access to.