1970 8/E $6,500/$40,800
1972 8/F, 8/M ? less expandable
1974 8/A $1835/$9000
8/E two backplanes, 8/F, 8/M one backplane. One was for OEM's.
8/E relatives seems to be the most common that shows up and reasonable size. Normally use OMNIBUS controllers for peripherals but can use older with interface cards.
8/A's less expensive currently though don't show up as often as 8/E's. Frequently don't have the programmer panel.