There is a way to find the value of another card! Any other card!
The URL of your own deck is https://www.nationstates.net/page=deck
It is also https://www.nationstates.net/page=deck/nation=[nation_name] (Take out the brackets and nation_name, replace with the name of your nation, just like the regular nationstates.net URL.)
For example, I can see the deck for my puppet nation 71X by changing the URL to https://www.nationstates.net/page=deck/nation=71x (Also note I have checked on a nation that has cards and can confirm it is NOT possible to mess with their deck. However, you can place an offer to buy any card displayed in their deck.)
In the upper right-hand corner where you can view your card, you can now view the card of the nation you've selected. In my example, the card for 71X is https://www.nationstates.net/page=deck/card=1764694 (Again, you can place an offer to buy the card selected.)
Hope this helps; happy card collecting!
