Hello,
The 50 Kč only has a very little value, being circulated and not really rare. All the other banknotes are still exchangeable for their face value at the Czech National Bank.
200 Kč should have a bit more value than its face value (which is approx. 8€), as it is an older prefix in a decent state. Same goes for the 100 Kč, but only if it really is UNC (no folds or any other damage). As for the two remaining banknotes, I suggest either offering them somewhere for their FV (about 60 €) or exchanging them in the National bank if you ever travel to the Czech Republic.
So the whole lot would have the value of approx. 75€, or maybe a bit more if you find a right buyer.
