If you don't want to buy it outright, you can play it "for free" if you already pay for these services:
The Classic version is often included in the library for console and PC. Star Wars: Battlefront 2 (Classic) Free Download
Occasionally given away for free as part of their weekly rotation (though this more commonly happens with the 2017 reboot). 2. Subscription Services If you don't want to buy it outright,