Royal Rudolstadt Tea Set

I would love to know the value and age of this set.  It is in excellent condition, with no chips or cracks at all. It is clean and the colors are consistent and vibrant. I beleive that it is complete and not missing any peices. It is such a sweet little set.

 A woman donated it to my shop because it had belonged to her Grandmother and she couldn't bear to look at it once the Grandmother passed away.

 I have seen peices of this set selling on the internet for such a wide range of prices that I can't quite figure out what a fair value would be for the set.  Any information or help is greatly appreciated.