Expenses are relative, I would look at it in opportunity costs, what's more important my health or a car payment? I'll take health. The symptoms of low testosterone are insomnia, low libido, depression and increased risk of heart failure. I'd gladly pay $400 a month to avoid that.
You could always give this a shot in one of those countries that does medical tourism. Thailand has some excellent hospitals that serve a lot of medical tourists (who tend to get things done like Lasik and cosmetic procedures), that I bet would do this for pretty cheap. Of course, getting there isn't exactly inexpensive, but it's an option.
It's at this point that I feel the need to clearly state that I'm in no danger of needing this any time soon :) Though Thailand would be wonderful for regular tourism, medicine aside.
Just sayin'. I was thinking of getting my vision corrected a few years back, but between the cost and the recovery period, given my professional life at the time I decided against it. I still kind of think I should have done it though. Thailand is a lot more family friendly than many young tourists want others to believe.