What do the merchants buy from me?
There are many hundreds of automated merchants and shopkeepers throughout The City.
Naturally they're not all the same. They sell and buy different stuff, to different people, at different times of day, depending what tattoos the customers have and whether they bow first and what day of the week it is and on and on.
Many merchants will both buy and sell. Of these, most will buy items similar to the ones they sell. So, somebody who sells shoes might buy them too. But a merchant who sells shoes maybe isn't interested in buying daggers.
Note that different merchants charge different prices for the same Items. It's likely that the merchants who charge more for an Item will pay less to buy it from you. So, explore, and ask experienced players for advice.