sometimes we do local trades in our closer playgroup.
and sometimes we both want cards, but don't have enough to even it out.
as times goes on, prices fluctuate.
it could be really helpful, if we could see it later (1-2 months) what was the original trade, so everyone can go even.

I find this useful as well.

As a suggestion, write the trade value in the chat when commiting to the trade, then you have it stored :)