The first generation Tempest was sold from 1961 to 1963. It was a compact car, but it was sold as a coupe, 4 door sedan, 4 door station wagon, and 2 door convertible. I'm not sure how a 4 door station wagon could ever be considered a compact car, but the standards of the day were different than they are now. The base engine was an I4, but there was plenty of room under the hood for something bigger. The top engine choice would be a 5.3 liter V8. A very small number of Tempests were bought with a 3.5 liter Buick aluminum V8 engine. It weighed just 330 pounds but could make 215 horsepower.
The second generation Tempest was sold from 1964 to 1972. All of the body styles were back, but the engine was moved from the rear to the front. It was based on the same A body platform, but it would no longer be similar to the Chevy Corvair. It was now more of a midsize car that fit in well during the muscle car era.
The Tempest LeMans performance version of the second generation Tempest was spun off into its own model line, the GTO. That car would go on to be considered the pioneer of the muscle car era, so the Tempest can be credited with having a small role in creating that period of cars.
Some Tempests, such as the aforementioned aluminum block Buick V8 models from the first generation or the Tempest Super Duty built in 1963, are considered classics today. Even many of the others are collectible with the right options and the right conditions. Find prices on eBay to figure out a price range for an individual model year.