Chevy liked the idea of these cars so much that they made a competitor for in 1959, named the El Camino. It ended up becoming the more popular of the car/trucks.
There were 6 generations of the Ranchero. They were: 1957 - 1959, 1960 - 1966, 1967, 1968 - 1971, 1972 - 1976, and 1977 - 1979. They were all front engine, rear wheel drive vehicles based on car platforms with either an inline 6 or V8 engine. Transmission options were either a 3 speed manual or a 4 speed automatic.
These cars are considered collectible, especially the pre-1970's models. They are often overlooked by collectors in favor of the El Camino, but I would expect their collectibility to even out over time. About 500,000 Rancheros were produced during its lifetime, which is a fairly low number considering it was around for over 20 years. You can find plenty of them listed on eBay in all conditions, from original unrestored to completely restored and even a restomod or two.