Ithaca M66 Super Single 12-gauge, 3-inch chamber shotguns sell on Gunbroker.com for $50 to $125. In excellent condition, these shotguns usually sell for $100 to $125. In poor condition, they sell for as little as $50.
The M66 Super Single 12-gauge with a 3-inch chamber was produced from 1963 to 1978 and sold for around $30 in the earliest production years. It featured a lever-activated, break-open design that was unusual for shotguns. The year of manufacture for a specific M66 Super Single can be determined by comparing the serial number to listings of serial ranges by year in a PDF document on the Ithaca Gun Company's Web site.