The MathWorks does not offer older versions as freeware. However, there are :
Searching for “MATLAB 2008 download free full setup” leads you to many suspicious websites. Here is what you risk: MATLAB 2008 Download Free Full Setup
Before attempting to download and install a setup of this age, it is vital to ensure your hardware can actually run it—or conversely, that your modern hardware isn't too new for it. The MathWorks does not offer older versions as freeware