Here is a 1920's Stock transfer of the Louisville Baseball Club certificate with some stamps on it (there are also about 16 more stamps on the back). I sold this on ebay for the hammer price of...............$10. That makes each of these stamps about 50 cents if that. I am not sure if these are the kinds of things you are looking it or not. I have also owned a ton of old documents with Revenue stamps on them and they have never sold for much so I cant imagine Revenue stamps themselves being worth much, but I am not a stamp guy. In my opinion, these are not worth a whole lot but I could be wrong.