You can find the game on official storefronts and authorized retailers:

The Complete Edition removed and the original multiplayer modes , focusing strictly on the single-player experience. For improved performance on modern systems, many players use the Fusion Fix mod to resolve stuttering and graphical glitches. Grand Theft Auto IV: Complete Edition - Rockstar Store

While is not officially available for free, it is frequently discounted and remains available for digital purchase on major platforms. This edition includes the base game along with the Episodes from Liberty City expansions: The Lost and Damned and The Ballad of Gay Tony . Where to Buy