So many colors, so many prices
These are powdered mineral pigments and used in Japanese painting, added and mixed with glue, a material for fixing color on papers.
In natural pigments, made from powdered mineral, blue is higher than red. But this shop sells blue at lower price than red, so these colors may be made from artificial materials.
By the way, blue color tend to be also lower than the red in oil painting. Piccaso would use only blue and the time is called "the blue period". Some book say that Picasso only used blue because of his deep sorrow and grief. But other books say that he only used blue partly because he had little money to buy the materials...