..."where your mouth is" definitely applies here.
Okay, so you should probably not buy items like this in a pharmacy where they are naturally more expensive, but sometimes duty calls.
I just had to know how much this would have cost in the US, and I guess I shouldn't have looked. Seven euros and eighty-five cents is the equivalent of $10.36! I found this online (actually, a more costly version with the teeth whitener built in) for $4.29 on sale at Walgreens.