The easiest, quickest, and best way I found to scan thousands of photos was to purchase an Epson FastFoto scanner. You stick a whole stack of photos into it, it scans them one after the other amazingly quick, then you stick another stack in and keep going. I did this with boxes of old photos of every size, some of which I literally had to cut out of photo albums. There are options for scan quality and resolution. It helps tremendously to have your photos organized for how you’d like to store them, so for instance have your 1989 Grand Canyon photos together so that they can be named and numbered as they are scanned. It will even scan the back of the photos if you have writings or labels you want to preserve. This might not be the cheapest option, but its fits your other criteria perfectly.