If you are looking for older King's Quest titles, several high-quality fan remakes are legally available for free:
If you want to play beyond the first chapter, you have a few options: King’s Quest (2015) Complete Free Game Download...
: Grants access to Chapters 2 through 5. This is often the cheaper path if you already have the free first chapter, though it typically excludes the epilogue. If you are looking for older King's Quest