It looks as though you have some coverage of later, modern Poland.
My suggestion to you would be to group all of your Poland together, and put it on
ebay. That will really be your market right there. You've already gone to the trouble of getting plenty of photographs - just pull out the other countries. Having a couple US mixed in with Canada and such makes it look like a hodge-podge and detracts from the appearance of coverage I get with your Poland.
As to value, I would suggest looking at
ebay past sales of Poland collection. That will give you an idea
With the other countries left, you might offer the Czech, Romanian, Hungarian, Mongolian separately later to pick up a couple extra dollars.
Selling in the forum is restricted to those with 50 posts....
Best wishes.