This computer costs about $850 currently and if you were to buy this model you really would not have to do a lot when it comes to upgrades. It already has 16GB of RAM and a fast SSD drive. I guess you could add a larger SSD drive but for my purposes the size is fine.
This is a 2012 computer so at five years old it might be a good ideal to replace the battery but that should only cost you about $30.00 or so. An extra charger would cost about $150.00 if you need an extra power supply as the battery life on a a 2012 model isn’t as great than with a newer MacBook Pro.