Vendors at School

I don't know how it all works, but there are vendors who come into school to sell things. The range of items baffles me a bit.
We regularly see the "stationary man" who's always smiling and bowing at everyone. He's in charge of school supplies needed for classes.
On other days, there's the Yakult yogurt lady who comes in to sell soft drinks after school. Unfortunately, the last time she came in, 90% of the teachers were in a staff meeting. Her visit seemed wasted, but she still stood there for a while hoping for business to come while chatting with the tea lady.
Then, two days ago, a lady came with the most random assortment of goods. Her wheely cart of goods included tea, dried foods...and body-slimming ladies underwear!!!
The funniest thing was that two of the female teachers actually went up to this lady in the middle of the staffroom and discussed the product's effectiveness! The lady even unwrapped a package of the underwear to convince the teacher that it's of good quality.
I couldn't keep a straight face when I saw all of this, so I had to hurry to my desk and acted like I was laughing at something else. It's a shame because I would like to know if she had made a sale.

Japanese school staffrooms still baffle me. =)