Spiekeroog, Germany Postcard To Latvia Need Help With Stamp Id.

I just found this going thru some old papers that I was getting ready to toss. The postcard is of an old house on the German island of Spiekeroog in the North Sea and was mailed to Kurtenhof, Russia now Salaspils, Latvia. I've always enjoyed mail of the period that seems to arrive before departing because of the 2 calendar styles back then. What I need help with is an ID and a value for the stamp if someone has a minute. My nearest available Scott's Catalog is in a library 20 miles from where I'm sitting and I normally only collect Latvia. TIA

It looks like Michel Nr. 86Ia (your card is from 1907)

Thanks a lot perf12