Well! to start with, the "items" being traded were just variables. the merchants' dialogue was set up as a conditional dialogue, so depending on the count of certain variables they'd say different things. then, when they were supposed to give you an item, I used {VariableName = 1} to set VariableName to 1 - ie: to "give" you VariableName. This variable was then used in a different merchant's dialogue, and so on.
The Bazaar had plenty of worthy baubles, but this clear explanation was absolutely priceless.
I'm just getting started with Bitsy and I was figuring out the variable elements mostly by trial and error.
This one comment saved me lots of guesswork and helped me finish my game in time for the Bitsy Jam deadline this month.
Thank you so much! Really grateful for the help.