u/Didjbdhd

I'm looking to change the battery on my 2011 328i and need some pointers.

All I'm looking to do is get my car running so that I can sell it. I've already been quoted 10k (Canadian) from the dealership to do other repairs (brakes and brake lines) and the car has 190 000 km and has been sitting for months.

Questions:
Should I be splurging on the H8 battery again or should I just get it running on something smaller?

Do I need an OBD 2 sensor? Or would I be able to get buy without it? Just to get the car out of my driveway and into someone else's. If I do need one can I get by with a $40 amazon one?