Before your child charges into a real estate purchase with checkbook in hand, you should walk him around his or her neighborhood of choice to check out comparable homes. There's an old saying in real estate, "You don't want to own the most expensive house on the block." You also may not want the least expensive, and checking out the comps will allow you to figure out where you fall in between that range. Look for houses with equivalent square footage, and a similar number of bedrooms, bathrooms and amenities. The prices on those homes should be comparable to how your house is priced. Beware of properties that are unusually high or low.