The subsidies only start after you earn a certain amount of income. If you earn less than that, you don't get any subsidies. Also, the subsidies won't pay for all of it, and the more you earn, the less subsidy you get.

The original plan was to force the States to extend Medicaid (Government provided health insurance) to cover those that would not be getting subsidies because they made too little. The problem was, the Federal Government was only going to float the bill for this for a few years, then it was going to be up to the States to come up with the money to keep it going! Many States balked and refused to expand Medicaid, citing the fact that they could not afford this massive increase in their budget. The Supreme Court agreed with the States that the Federal Government could not force them to expand Medicaid unless the Federal Government was going to float the bill.

So now, anyone that doesn't earn a certain amount of money will be without health insurance, and the cost of healthcare will be higher for them when they do get sick (For many reasons, such as the medical device tax). Fortunately, for now, if you live in a State that did not expand Medicaid, and you would have qualified had they expanded it, you won't have to pay the penalty tax.