I used to handle Nolte's work and it wasn't inexpensive. In the mid 80's his smaller images (4" x 5")were in the neighborhood of $150.00.
The biography I have: (The literal translation from German)
"Udo Nolte was born in Dortmond,West Germany May 16, 1950.
After school-time he studied at special art-institute in Dortmund for more than five years design.
Then, having passed the state examination, he went to university in Bochum for studying history of art until 1978.
Since 1979 he earns his living for his wife and himself with liberal art, especially etching. His works are distributed by galleries in whole Europe and since a short studying visit to San Fransisco, California, also in North America.
Permanent exhibitions of Udo Nolte's etchings are taking place in Western Europe and abroad."
I bought what I had from Ted Schwartz Fine Arts. He left Florida a while back and moved to Colorado Springs, and I have lost track of him.