Earlier this year I sold a few items I no longer needed on Facebook Marketplace. I checked the prices of similar items, and set my price at the average for comparable products: about £50.
After 24 hours, I had received no messages of interest, so I dropped the price by 20% to £40. All of a sudden my inbox was flooded with messages—it was a night and day difference. The theory bells from my Economics 101 less on the price elasticity of demand were ringing.
It’s impressive how fast these second-hand markets move and calibrate to an collectively agreed going rate.