Kalakaua Inn The Kitchen Hostel AO

This backpackers-style hostel is conveniently located near Kencho-Mae Station in Naha. They have a super deal where you can stay a night for ONE YEN if it’s your birthday month (you’ll need to show proof), or 1,000 yen/night for your group.

This applies to weekdays only, and you’ll need to book directly through the hostel website (in Japanese).

If it’s not your birthday any time soon, or you can’t wrangle the Japanese booking, don’t worry, as their regular rates are very reasonable, and start from 26USD/night.