NEW YORK ( TheStreet) -- If you're looking for the best deal on a used car, some national auto search experts have a special message for you: Cool your jets for 30 days and save 5%, 7% or even 15% on that car you really want. Sure, by stalling, there's a risk in losing it. But the folks at iSeeCars.com (who follow this sort of thing), say cars last on a lot longer than you might think, and that a little patience waiting on a used car can easily net you four figures in savings. According to iSeeCars.com, an analysis of 30 million used vehicles shows that the price for many of of those cars and trucks were reduced by 7% before they were sold and driven off the lot. auto dealer lots for an average 31.5 days, the strategy is simple -- if you have the patience: Identify newer used cars that just rolled up to the dealer; note the price; and come back every week for 30 days. By week four, the online car search firm says, the price of a used car costing $18,000 could easily fall to $16,800, saving you $1,200 in the bargain. If you just can't resist temptation and don't want to lose the vehicle, that weekly visit should still result in a lower sticker price every time you visit the dealer. According to iSeeCars.com, used car dealers cut the price on the average vehicle between one and six times over that 31.5 day listing period. The first price drop is significant -- the firm says that the price drops, on average, by 5% the first time the dealer rips the old sticker off the car and pops a new on. NSANY) 300zx, which dropped 14.7% in the period it was tracked by Phong's firm. Or how about a Chevy ( GM) Cavalier, which fell in price by 13.7%? Yes, waiting to buy your favorite used car using this strategy isn't fool-proof. But it does offer you a great potential deal: 5% to 15% off on a good used car or truck, just by waiting 30 days.