Mass merchandising methods can be applied to selling homes, according to real estate experts who have studied how homes are priced. It's not unusual for the same techniques used in selling consumer goods to be used in home selling. Though not a particularly straightforward method of doing business, the use of ''broken price points'' (like $9.99) has proven effective in moving the merchandise. The most difficult hurdle, experts say, for a real estate sale is at the top of the $100,000 or $200,000 bracket. Experiments have shown that prices like $99,500 or $199,750 have a tendency to enlarge the looker market.