How much is a used unlocked iPhone 5s worth?

Back in Jan, I sold an unlocked mint iPhone 5s for $179.

I left the ad up on Nextdoor and have since had 2 inquiries on whether it is still available.

I must have sold it too cheap back then!

Hard to say, for maybe, given the 9 months gone by, the phone has gone down in value, or maybe not. Just looking at a few current prices, it seems as if you sold for an acceptable price.