One of the most surprisingly successful government efforts to stimulate the modern auto industry is coming to an end -- and much sooner than expected.

The Car Allowance Rebate System, better known as Cash for Clunkers, is scheduled to end on Monday, Aug. 24 at 8 p.m., (though dealers will have until noon the following day to file their paperwork). After doing an extensive amount of analysis on the amount of deals already locked and pending in the system, the government chose to not fund a second extension to the program, the Department of Transportation said.

Even as dealers throughout the country voiced concern over the delays in processing as of Aug. 20, DOT had processed 170,000 applications, or just under 40% of those submitted, and paid $145 million to dealers they would be hard pressed to deny that the Clunkers program has provided the energy shot the auto industry so desperately needed.

What happens next? If you re planning to buy a new (or used) car soon, you ll find your experience may be quite different from that before the Cash for Clunkers program began. Here are five changes to expect:

1. Thinner inventories leave shoppers with fewer choices

Inventory is really the key issue for car shoppers, at least in the near term, says Jessica Caldwell, a senior analyst at automotive data aggregator Edmunds.com who has been tracking auto sales under the Clunkers program. The program s success depleted dealer inventories faster than anyone anticipated, even as manufacturers ramped up production to meet new demand.

Tammy Darvish, vice president of Washington, D.C.-based Darcars Automotive Group, says her dealerships now average a 25-day supply, compared with a typical 50-day supply before the start of the Clunkers program. If you re in the market for one of the popular models Ford (F) Escape, Focus and F-150 models, Honda (HMC) Civic and Toyota (TM) Corolla and Camry, according to Edmunds.com you ll be better off waiting several months for inventories to build back up.

2. It s still a seller s market in the near term

Cash for Clunkers stripped buyers of some of their negotiating power, and they may not get it back in the near future as dealerships remain emptier than usual. In the short term, at least, higher prices will be holding up because of the inventory issue, Caldwell says. But at one point, the market will correct itself and, incentives or not, with a fully-stocked showroom the dealer will have more room for negotiation.

3. but expect a return of manufacturer incentives soon

When it comes to incentives, consumers are easily spoiled: Once they re offered a good deal, they start to expect more going forward, says Thilo Koslowski, a vice president and lead automotive analyst at market research firm Gartner, which tracks retail trends. To get consumers to go to the showroom without that additional incentive will be tough, and it puts the burden on the manufacturer to phase out of the Clunker program, he says. And that s where new incentives come in, he adds.

4. Good news for the value of your trade-in...

By the time the $3 billion in government rebates is exhausted, the Cash for Clunkers program will have taken nearly 750,000 old cars off the used-car market (clunkers are scrapped, not resold). Add to that a significant decrease in leased vehicles last summer General Motors and Chrysler pulled away from leasing, though GM recently re-entered the market and in the near future you re likely to see fewer used cars to meet consumer demand, says Jeff Bennett, a professor of automotive marketing at Northwood University in Midland, Mich.

Already, used-car values have increased markedly over the past three months and will likely continue to do so, Bennett says. That s particularly good news for car owners who are upside-down on their auto loans, or owe more to the bank than their cars are worth. The average individual who owed $20,000 on a car that was worth $15,000 may now have a car that s worth $16,000 or $17,000, Bennett says. They ll be in a much better position to trade in.

5. ...but a short-term hit on late-model used cars

If you have a later-model car, don t rush to the dealership to trade it in just yet: Chances are it is worth less now than it was before the Clunkers program. With its $3,500 or $4,500 rebates, the Cash for Clunkers program convinced many consumers to buy new cars rather than recent-year models, which depressed prices, says Jack Nerad, executive market analyst at Kelley Blue Book, which compiles new- and used-car pricing data. Values may begin to rebound once the program is over.