In celebration of the 10th anniversary of Half-Life, Valve is now offering the company's debut title for just 98¢. Launched 10 years ago today, Half-Life was greeted with overwhelming review scores (Metacritic of 96%), earned over 50 Game of the Year Awards, and birthed a franchise with over 20 million units sold to date. The special 10 year anniversary price is available via Steam until 12:01 pm PST on November 21.