I recently found my brother-in-law Mega Drive in pristine conditions

File: Sega-Mega-Drive-JP-Mk1-Console-Set.png (383KB, 1060x530px) Image search: [Google]

383KB, 1060x530px

I recently found my brother-in-law Mega Drive in pristine conditions and was allowed to use it. I never had a single Sega console in my whole life so, except for a few times I remember playing that Michael Jackson game in a cousin's house, it's essentially a new experience and, as much as there are charts around, I'd like do ask a few questions to my fellow /vr/ Troopers.
- It's a japanese version (3-button pad), with no games. Pretty sure it doesn't have region locks, but are there physical cart locks like the SNES?
- This one will sound silly, but what are the best games to start?
- How bad is the aftermarket price? How much is an average fair price? Is it worth going for a flash cart?

Thanks in advance.