Tracking rates, closing costs can help you avoid overpaying for a home loan

— -- Tired of the bar scene? Skip happy hour and visit some open houses in your neighborhood. Faced with lackluster sales, real estate agents and sellers are spicing up their open houses with wine, live entertainment, hot towels and door prizes. And while you're sipping complimentary chardonnay, you can check out your neighbors' window treatments.

And who knows? You might stumble on your dream house, at a price you can afford. Still, even in a buyer's market, you could end up paying more than you expected. Let's look at two factors that could raise the cost of buying a home — and how to avoid them.

Rising mortgage rates.

Average rates for 30-year, fixed-rate mortgages were 6.26% last week, the highest since March, according to a survey of large lenders by Bankrate.com. A survey by HSH Associates, which includes rates on "jumbo" mortgages for higher-priced homes, puts average rates even higher, at 6.7%. And there's a good chance that mortgage rates will continue to climb in the weeks to come, says Bob Walters, chief economist for Quicken Loans.

A sharp jump in oil prices has heightened concerns about inflation, thereby pushing up rates on long-term government bonds. That's led to an increase in long-term mortgage rates, Walters says.

By shopping around, you might be able to find a lower-than-average rate, particularly if you have good credit. Once you find an attractive rate, you should lock it in, Walters says.

The downside to locking in a mortgage rate is that rates could drop, leaving you with a higher rate than you would have gotten otherwise. But if that happens, Walters says, you can always refinance; all you'd lose is the cost of refinancing your new loan.

On the other hand, if you don't lock in a rate, and rates jump, you could lose thousands of dollars over the life of your loan. "If you lock in at 6% and close that loan, and interest rates go to 7%, 8% or 9%, you've hit a monstrous home run," Walters says.

For most home buyers, a 45-day lock is sufficient, says Cameron Findlay, chief economist for LendingTree, a website that lets borrowers shop for loans. You might have to pay extra for a longer period, he says. And make sure you're dealing with a reputable lender that will honor your locked-in rate.