Most federal loans these days are at 6.8%, and max out at around $5,000/year for undergrads (which is only half the cost of tuition at a state uni here). Private loans tend to lean more towards 8-12%. Also, good luck even qualifying for the latter if you don't have a rich parent with collateral to cosign for you.

It's a good thought, but I think it's much less useful today than it was in the era of 2-3% interest student loans. My teachers always use amazingly low interest rates in math problems and then get all shocked when I mention how much even the government charges these days.