This is a great deal for all three Witcher games including all DLCs.
Instead of Witcher 1 and 2 you can also pick other games from the Witcher Universe.
If you already own some Witcher games and pick pick higher value games the prices go down further.
For example if you pick the following the prices are as follows (also depends on what you already own on GOG):
- Witcher 3 Goty: $15.79
- Thronebreaker: $12.00
- Adventure Games: $0.59
But whatever your situation, the prices for the Witcher games are great at the time and since CD Projekt Red is the developer and is owned by the owner of GOG all your money supports the developer of the games.