Fred (I assume),
That is a good price. My lease buyout was at $19.5K on a 2017. You can probably negotiate lower. With the exception of initial issues with 2014 motors and some rarer motor issues with 2015-2017, EVs are usually trouble free.
You will want to confirm the remaining warranty on car AND the battery. The latter requires annual MB inspection, if skipped, no warranty.
The extras are:
1. Get an extended warranty that covers the electrical, motors, and battery. A couple of grand (look up post on this as I forget).
2. If you need parts, as a discontinued model, getting harder to get original OEM. Normal for any discontinued line but this one only ran for 4 years.
THIS IS A PERFECT GETABOUT, WHETHER YOU LIVE IN URBAN OR SUBURBAN. Plus you know all about charging or your wife does and she can tell you.
Jeff in NYC
MB '06 E500W; MB '81 380SL
Retired: MB '17 B250e; MB '14 Be