Surge protector for the TV for sure.
The apartments you were referring to are in the ¥200,000 to 280,000 range. O-3 gets you around ¥207,000/mo. plus you get several hundred for utilities that can go towards the difference.
Agree with pilgrim, no need for a Japanese bank or the one on base for that matter. Look into the Amex platinum/Hilton cards if you don’t already have them.
Some places take card some don’t. I always keep around 100 bucks worth of yen on me.
You can find cheap cars in the lemon lot and off base but you’re going to have to pay cash so be ready to take out 3K plus out of the atm (the atms on base only allow $500/transaction so it takes a little while). Get smart on how road tax/JCI works here before you buy (your sponsor will know).
Also, you’re going to need to pay around 5-7K to get into your apartment (at O-3 pay you’ll pay first months rent ~2K + ~2K security deposit + ~1K agent fee + some possible other move in fees) and that is all in cash (this from all my bros’ and my own experience) so know how to change you’re withdrawal limit in your card. The good news is everything is reimbursed by housing except the security deposit.
Not all apartments allow American appliances (W/D, stove, fridge) so keep that in mind. Japanese appliances are most likely not what you want. The good news is you can get the American appliances from base for free.
PM me with other questions.