I take it that you're not buying it from a BMW dealer....
A BMW dealer will do an inspection for you at their normal labor rate. You might get them to check to see if it needs a software update or some other service campaign to be performed, and before the 4-years up, those would all be free, and some may be free afterwards if there were a recall.
All of the i3's come with a level 1 EVSE in the USA. This plugs into a 120vac circuit...ideally a dedicated 15A circuit, but it could share (but depending on what else is on that circuit, you may need to tell the car to lower the charge it takes. That, along with an air compressor with a can of tire repair goo in it and a screw in tow hook are the only extras normally in the front trunk.
I don't think the car will have any 'free' charging left, but you'd have to talk to BMW. You will want to get the BMW connect and emergency connect reassigned to you so that you can also use the BMW connect app to monitor and do some remote control things with the car. The BMW extra functions came free for 3-years, but you could transfer them and pay the annual fee if they are important to you.