A pink salon, or pinsaro for short, is a type of brothel in Japan which specialises in oral sex.
A pink salon is unusual in that the service is offered in small booths within a large open-plan room. The client is served soft drinks or alcoholic beverages by the "companion" who performs fellatio on him. There may also be additional activities such as fingering the "companion".
Are they legal?
Yes. Prostitution in Japan is illegal , but Japanese law has a rather Clintonesce few to sex. Fellatio isn't classed as sex. Only contact between genitals is included in the prostitution laws. In fact, anal sex is legal too as it isn't genital to genital.
How much does it cost?
A twenty minute session with one girl is between $30 and $50 dollars. A two girl session ( one after another) is double that. Prices vary at times of day or night. Day times of course cheaper.