Hello and welcome to the forums. Is this your radio:http://www.radiomuseum.org/r/graetz_grazioso_530.html
If so, it's a nice looking set! The only price I could find was on the website above (you have to be a member to see prices). The 2005 price as sold on eBay Germany was US $156. If it's in good, working condition, I'd say the prices could range anywhere from $50 to $150 US, if you can find the right buyer. Console radios, whether they are US or European, are rather large and a lot of collectors will stay away from them for that reason.
If this is a set you are wanting to use, then it should be restored electronically before you put it in use.
Good luck, and let us know if you have any futher questions.