The recent trade-in price history of IPhone 13 Pro Max 128GB generally shows an increase. In other words, the used prices of this device are getting higher as it is becoming more desirable. This normally happens if your device is reasonably old and may appeal to those on a tighter budget, or (more likely) people who are looking for parts. It may even be to strip down or re-sell in a third-world country - here's why. Remember: It is very unlikely that prices will keep on increasing for ANY used electricals.