Avi - you should really introduce yourself properly - i.e. how long you've been collecting etc & what you collect. That would help...
The values I listed are 'catalog' values. Market value & catalog value are not the same!
Normally, folks like to buy stuff - depending on lots of variables - at 5-25% of catalog value. For example, a normal postcard of the (common) types you've shown - I would buy at between $1-$5 max. And that would be in decent condition.
Yours, for example, seems to have a major crease down the middle. That would significantly detract from its value, as far as I'm concerned.
But none of this discussion is talking about the negative cancellation. I don't have values. Nigel (whom you'll learn is an amazingly knowledgable collector!) doesn't have a value - he is indicating it is rare - a fact with which I agree. But the only catalog we know of - (and I don't even know if it has values?) - is a 10 volume set that costs app $1000. (Nobody who frequents this forum has one, to my knowledge...)
The best source of 'market value' is
ebay - what people are paying for stuff. You can search for it & see what similar items have sold for recently.
Is your postcard on 'paperlike' thin cardboard' or thick like a normal postcard?
If not, its catalog value is between $20-$40. If it is, then it is a very scare & high value item!!
Please post a complete picture of the 2nd item as well!!