I also think that trimmed cards have very little value, other than sentimental. It is the equivalent of a pottery piece with a crack or chip in it... While it may still be nice to look at, the damage makes it unsaleable and virtually valueless.
About a year ago, I also was the unhappy recipient of a trimmed card. It was otherwise a very nice real photo postcard, but since I had paid $50 for it (yes, for one card!), I asked the seller to refund my money. He agreed, but when I mailed him back the postcard to receive my refund, he claimed that he never received it!
I have mailed hundreds of postcards over the years and the only one ever lost in the mail (up to that point) was a postcard sent to France around Christmastime. So, I found it hard to believe he never received the returned postcard. I think the seller just didn't want to refund my money, so was claiming non-receipt to wiggle out of his obligation. Since I had insured the postcard, I was eventually able to get the $50 value back from the Post Office, but the clerk told me that there is no trace on items insured for $50 and under. In other words, the seller may have indeed received it, but there was no way for the Post Office to verify delivery. Although in the course of the Postal claim, the seller had to sign an Affidavit (which I also had to mail to him --- more money out of my pocket), I still believe that he received the postcard but kept my money.
The postcard has probably since been unloaded onto another unsuspecting fool. What I learned from this is that in the future, when I plan to bid $50 for a postcard, I will ask the seller to email me a scan of the reverse side to be sure it is not trimmed.
