I'd do some research before you said yes, because my guess it it will costs 4 or 5 times $20 to ship it to Germany. Plus I would make sure the buyer was aware any duty would need to be paid by purchaser. I just spent 10 minutes online trying to come up with a cost from UPS, and all I could get was that I would need to call them.
I am sure there are others who know more about international shipping than I, and perhaps they will have better info. But to me it sounds expensive.
Ron