Daily free spins can be a very lucrative bonus. But they are also pretty costly for the casino's. Imagine giving 200 free spins on a deposit of only €10. The initial value will be around €40 already, but if you win during free spins it can even be much higher! That is why daily free spins are pretty rare.
The casino's that do offer them can be found on the following page. Just sign up at any one of them, and make sure to read the terms and conditions carefully.