----- Since Rakuten ETC card came, I decided to buy an ETC onboard unit. When examining the market price on the internet, it was around 15000 yen with installation fee. Asking the dealer, they give us a quote of 27540 yen. Too expensive! I answered "I will consider it" and left the dealer.
ETC compatible with ETC 2.0 is about 12000 yen. Old ETC is around 6000 yen. It would be cheaper when using "Ken oh do" road with ETC 2.0 so far. Then old one is enough for me.