Very early '80s. There was a promotion in the Bay Area by a home-electronics store, "Matthews, top of the hill Daly City!!!!" that gave away that bike (or MTB version) with every $40 or more purchase. If they're making money on the electronics AND giving away a free bike, you can imagine how good the bike was.
Anyway, I bought $40 worth of stereo equipment for the dorm room and got the MTB because I needed a bike to get around school anyway. It came in at a helfty 38.5-lbs with all steel parts. Not a scrap of alloy on it anywhere. But it was bulletproof and held up for my 6-years of abuse and neglect without any problems and minimal maintenance (other than oiling the chain, adjust the derailleurs & brakes).
Yeah, don't pay more than $20 for it and you better be good mechanic. It may require $100 or more in service from a bike-shop.