You can download Death Rally for free from Remedy’s web-site, as they have made the classic racing game available as freeware on their web-site. Meaning you can download the game without a penny paid and enjoy it for as long as you want. 
Remedy is the company that made the Duke Nukem series, and Duke Nukem himself even appears as a racer in the game! Death Race was released in 1996 and was Remedy’s first game.
From the Remedy site:
In late 1996 this top-down racing game took all by surprise with it’s addictive nature and excellent gameplay.
In 2009, Remedy is proud to announce the free re-release, Death Rally: Death in the Fast Lane for Windows. The original game, ported to run on modern PCs.
The basic idea behind Death Rally: win races, gather more money, buy upgrades to your vehicle. In between wreck your opponents, shoot your way through bystanders and keep the pedal to the metal!