story time!
i had a 2009 13 MBP on its last legs. being in grad school, i was highly dependent on my laptop and was in the market for a used macbook. i ended up purchasing a 2012 15 rMBP with a service battery issue for 650. from here, i sold my 13 for 250. so overall, it was roughly 400 to upgrade to the 2012.
well, i went to get the battery fixed at the apple store. apparently, that model's battery was in short supply until september. apple offered me a replacement refurbished model of similar specs since the repair was going to take too long. i agreed and they said the turnaround would be 48 hours. i wait a week (last saturday) and they call to apologize about the long time. they offer me a 2015 15 rMBP. my old model had a dGPU and so i pushed to get a model with a dGPU since they promised similar specs. apple offered me the model with the amd 370x, much to my elation. the next day i go to the store and pick up the model only to find it's only got iris graphics. i call apple and they offered to replace it with a tbMBP with a dGPU but they have to charge me the difference. i'm fine with it since overall i'm still saving a ton of money.
lucky for me, the store was out of stock of models and WWDC was the next day. i wait a week again and apple has no call so i ring them up and they notify me that they are going to give me the newest model at no charge. i just picked up the 2017 15 tbMBP and i'm shocked at the quality of the customer service.
400 bucks to upgrade from a 2009 13 to a 2017 15? i clearly have used up all my luck just now