I managed to nab a Subeautique item from the Free Shop at a time when I needed just one more purchase to "level up" the Subeautique Shopper achievement. I got credited for the achievement (so, um, thanks!), but probably this was not intended.

I can second this happening; I just got the achievement too after getting a Subeautique item from the Free Shop.

I don't recall if this was intended or not, but I know it has happened in the past, since the free shop tends to have subq items in it..hopefully one of the staff can answer for sure if this is supposed to.