I bought mine at AEON, in the school supplies section. Cost 198 yen. Then saw them all over town for 300 - 400 yen a pop. Kansai is expected to be cloudy that morning... ah well.
Schools in Kanto feared young children on their school commute would have accidents while walking and staring up at the sun, so decided to move the starting hour of school up by one hour. Other schools, keeping in mind the opportunity and the directive from the Ministry of Education to promote the event as an expansion of the students' minds with regard to science and the universe around us, promptly cancelled all classes for Monday.