> College is essentially free for many european countries, that is what I think sufficient level of subsidy
Most of the countries which people usually talk about here - France, Germany, Spain, etc. - have significantly lower matriculation and graduation rates than the US does.
I've studied CS 3.5 years for ~550€ per year (around $700). This includes free public transportation, but excludes an apartment.
In Germany, you can get a gov. funded student loan which can go up to ~750€ per Month. You have to pay back only the half of that. The 750€/Month is the highest amount that you can get. But you get it only if you have to pay the health insurance yourself, which is ~90€/Month. Otherwise, the maximum amount ~650€/Month. What you can get depends on the income of your parents. If your parents earn a lot of money, you get less.
What you have to pay back is capped to 10000€ in total, free of interest. So if you get more than 20000€ in total, you still have to pay back only 10000€. You even get a discount on that if you pay back early.
If you are taking this loan, your maximum debt is 10000€ (to be repaid only after the receiver exceeds a certain income level after graduation).
You don't get it forever, though. It is limited to 3-5 years, depending on what you study.