Chances are, you may not be saving as much on buying a home or making as much on selling one as you could.

That's because buying and selling a home isn't what it used to be and if you don't know what it is, what you don't know can cost you.

The Internet, new real estate buying and selling services, hundreds of mortgage programs from lenders and loan brokers, dozens more from government, grant and community agencies and a booming real estate market many say may be about to reverse are just a few of the elements that have changed the landscape.

That's the premise behind "How to Protect Your Biggest Investment", a Consumer Reports study of changes in the housing market and how you can benefit or suffer financially because of them.

The report includes a city-by-city look at how the housing market has boomed, zeros in on mortgage and home equity loans and tells you how to cut buying and selling.

"Buying a house followed a fairly simple scenario. You found the one you liked, went to the bank, got a mortgage, and moved in. Selling wasn't challenging either. You hired a real-estate agent, paid a 5 to 7 percent commission, and moved on. But no longer," the report says.

The report hits the high points of buying, selling and home ownership -- where you stand to save -- or lose -- the most. The full report is available only to Consumer Reports subscribers on or off line.

Here's a sample of what it offers.

For Home Owners

Fast appreciating home values have given home owners a fat cache of equity they can tap with home equity loans, lines of credit and cash-out refinancings, provided they are aware that any equity loan is also an equity-depleting loan.

Equity is best used for capital improvements -- home improvements, college education, business start-ups and other investments that provide an equal or better return on your money. One-time debt consolidation can be a good move as well, provided you rip up the credit cards and never go there again.

Shopping around -- on and off line -- for the best deal is the Golden Rule and Consumer Reports advises comparison-shopping by looking at loans with the same terms. Also compare all fees, monthly payments, and other fees.

For Sellers

• Not only are many housing markets a seller's market ,as many long time home owners site on a gold mine of equity, sellers also have a negotiating edge when it comes to who they choose to represent them. The growing option of discount brokers, for sale by owner (FSBO) services -- on and off line -- gives seller's more of negotiating edge when they choose a conventional real estate agent who has been around the block a few times, but wants to remain competitive.

• If you live in a housing market where prices have peaked and you've been thinking about downsizing to a cozier home, now could be a good time to do so. You'll need to do your homework, research the market and check home price appreciation trends, rents and the incidence of investors.

• "If rents are high and investors commonplace, the area may be on the brink of a drop in values, making now a good time to sell and pocket your gains," the report says.

For Buyers

• If you are buying a home, scrutinize mortgage brokers' fees, which can sometimes be "hidden costs" says Consumer reports. Brokers are paid to find you a mortgage from a host of lenders and they may be able to offer a deal you can't otherwise obtain on your own. The service could also cost you more than you need to pay because a broker is paid via fees paid by the lender and those costs could wind up in your loan.

Again, shop around by standardizing the comparison. Use the same cost factors with each comparison -- down payment, points, fees, type of loan.

• Buyers concerned about rising prices suddenly falling after they buy can reduce that risk by remaining in the home as long as possible, at least five years to give the market -- and your investment -- time to rebound. Also, keep your total housing cost -- principle, interest, taxes and insurance -- to no more than 31 percent of your income, Consumer Reports advises.

• Just like sellers, buyers have special choices for representation. An "exclusive" buyer's agent represents only buyers, perhaps for a fee the buyer wouldn't normally pay a conventional agent. A conventional agent, however, may represent both the buyer and the seller in the same transaction creating an often legal "dual agency" representation but one that comes with the potential for a conflict of interest.