"You get what you paid for"
This is true for many things, appliances included.
For example, if you buy a stereo for $80, it'll be better than a stereo for $50.
However, this is not the case when it comes to vitamins.
I've bought $30 vitamins that do nothing for me, and $5 vitamins that help me in at least one facet.
We already knew this, but I still thought I'd point it out. This saying, like any other saying, is flawed.