Best bet is to search completed auctions on eBay. My first guess would be not more than $5-10. Creased, wrinkles, straight-edge, short perfs at UR. While yes, it has a SON cancel, it's not crisp and fully readable, so in my mind would not justify a premium.
Take with several grains of salt, as I'm not a collector of duck stamps. I know that used examples are almost exclusively manuscript cancelled with the signature of the license owner, so a handstamped cancel may, in fact, be much more scarce... dunno.
Those stamps weren't valid for postal use and any purist would tell you that a postmark is of no added value even when applied during the correct period of use. I have seen many with fake cancels as there are a lot of devices of the modern era that have fallen into philatelic hands. However, the above doesn't mean that somebody wouldn't think they are worth a premium over pen cancel.
Comments
Take with several grains of salt, as I'm not a collector of duck stamps. I know that used examples are almost exclusively manuscript cancelled with the signature of the license owner, so a handstamped cancel may, in fact, be much more scarce... dunno.
1/2 Cents
U.S. Revenue Stamps
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