There have been two generations of the Rio. The first generation was produced from 2001 until 2005, and the second generation from 2006 until present.
There were few engine options on the first generation car. For 2001 and 2002 the 96 horsepower DOHC I4 was the only engine available. A slightly larger engine was available for the remaining years. Transmission options were the 4 speed automatic and 5 speed manual.
The Rio at one point only cost $6,995 brand new, making it the cheapest car in America and cheaper than the majority of 4-year-old used cars.
The only change in appearance during the first 5 years of production was a facelift in 2003. The second generation would bring greater changes, with the engine upgraded to a 110 horsepower I4 and better fuel economy. While the first generation only had a 4 door sedan and 5 door station wagon called the Cinco, the second generation saw the replacement of the wagon with a 5 door hatchback, called the Rio5.
There is a hybrid version of this vehicle in development.
These cars tend to be bought by teenagers and college students and then dumped on the used market a few years later. You can find them for cheap, and I mean really cheap, on places like eBay. We're talking about a few hundred bucks for a car that might only be a few years old.