If you're a remotely rational government, why would you not subsidize it? The dividends you could reap from a population with greater health, intelligence, self-control, low time-preference, etc., would be ridiculous.

Of course maybe people will want to use it for more zero-sum things like height or looks, so maybe you ban or don't subsidize that, but inequality in more positive-sum traits is unlikely.

Do you think the same as vaccinations? Those cost $x too: http://children.costhelper.com/baby-immunization.html

What if someone doesn't have the money for them?

I'm certain that at least in Europe, it will be free and regulated, if allowed.