Buy-back price in August generally has dropped in value across all brands. Value depreciate most noticeable on Android phones, with Google Pixel 2 XL see a drastic value fallen by $80; that is a 30% loss in value from the previous month.
Apple smartphone holds the depreciation value pretty well, with a $10-$30 dropped in prices across their models. The only exception is iPhone XS (64GB), which has the value plummet another $50 lower. However, given the model is almost a year since launch, having to sell it at $910 (SRP $1,649) is still a reasonable sum.