u/Vadaway

I keep forgetting to dip into the instant trade option, which I should do more because it’s pretty handy!
But when I do, the same sets aren’t always available to me. For example, the ‘we are the spark’ set is there, I trade a few dupes, then go back in to trade some more, and the options gone, even though I have more dupes available!
Can’t find the post that sets out how it works.
Anyone help? Cheers