Daily Free Spins generally have a high value, but it all depends on the slot to play, and how lucky you are.
Daily Free Spins have some of the highest bonus values you can find. This is due to the fact that you have to come back for them every day. A daily customer has high value for a casino and that's why they are willing to give you a big bonus for it.
How much the bonus is wordt depends on the slot you play, the value per spin, and how lucky you are in the end.
With a deposit of €10 you receive 10 x 20 (200) daily free spins on Book of Dead. The initial value of this bonus is 200x 0,10 = €20. This is already a really generous 200% bonus .
However while playing one of the days maybe you get really lucky! Say you win €300. These winnings are bonus money which needs to be wagered. After wagering you have €100 left. This is now your money, which you can withdraw if you would like. So instead of the initial value of €20 your spins might me worth much more. Please always read the t&c at the casino you are playing.