How to save some money
There are other less obvious ways savvy subprime borrowers can save money, too.

Consider that subprime lenders grade customers the same way that elementary school teachers grade children. Depending on an applicant's credit score, debt-to-income ratio, ability to verify income and other variables, a lender or broker assesses a letter grade that typically ranges from "A+" down to "D." The loan officer then charges a rate appropriate to that category. Because the distinctions between categories are often slight, borrowers can move up the scale without much effort.

For example, lenders tend to grade people based on how many times they were 30 or 60 days late with their mortgage payments in the past year. Having two "30-day lates" might push them into the "A-" category while having just one would keep them in the "A" zone. As a result, a customer who was late twice, but one of the late payments was 11 months ago, can improve a notch by just waiting a few extra days to borrow. By doing so, that customer could save a half a percentage point, or 50 basis points, on the interest rate, according to pricing sheets wholesale lenders send to mortgage brokers.

Scrounging up a few extra dollars can make a big difference, too. Lenders generally adjust their rates lower for each 5 percent drop in a mortgage's loan-to-value ratio -- the difference between the loan amount and the value of the property securing it. Someone with a $100,000 home who wanted to pay off debt by refinancing could save 50 basis points by getting a $79,900 loan rather than an $80,100 one.

Of course, knowing how to avoid rate hikes is just as important as knowing how to earn rate breaks. That's why borrowers might find it interesting to learn that lenders provide brokers with a list of things that will boost a borrower's rate. Some are things people have no control over. After all, if you're buying a condominium, you're buying a condominium and you'll probably have to pay half a percentage point more to do it.