Where to purchase GTA IV?

Just finished GTA San Andreas and all the GTAs previous to that. I’ve been doing replay-throughs of all the GTAs before VI comes out soon. I play on a PS5. I was wondering if anyone has been able to download GTA IV on the PlayStation store recently without having to purchase it bundled with GTA V which I already have. I’ve only seen it bundled and it’s insanely over $5. Thanks!