When a dealer or manufacturer has too many of certain vehicles and sales are slow, the manufacturer will encourage him to increase sales by providing a cash incentive. Right now, many car makers are offering big dealer cash on leftover 2009 models, as well as some 2010 models.

Dealers can use the factory cash in any way they want. Some spend it on advertising. Some hold special sales events or ”tent sales.” But in many cases some , if not all, of the money goes directly back to customers in the form of price discounts.

A car with a $2000 factory-to-dealer rebate will almost certainly sell for at least $2000 less than MSRP (sticker price), if not more. Frequently, manufacturers offer a combination of direct customer rebates and factory-to-dealer cash to make an overall sweet deal. Customers often negotiate additional discount from a dealer (it’s only right that a dealer should add a little of his own money) to make the deal even better.

Luxury car makers like to use hidden dealer cash because they don’t want to advertise customer rebates and be veiwed as a “discount brand.” That way customers can negotiate, or be given, a “special price” without it being so obvious that it’s a discount.

Here are some of the brands and models with the best factory-to-dealer cash deals. Keep in mind that these factory rebates can vary by region of the country and may be changed at any time.

2009 BMW 3-Series and M3 – $2500 dealer cash

2009 Chrysler Aspen, PT Cruiser – $4500

2009 Chrysler Sebring, Town & Country – $3500

2009 Dodge Sprinter – $5000

2009 Dodge Avenger, Durango, Nitro – $4500

2009 Dodge Dakota, Grand Caravan, Jpourney – $3500

2009 Jeep Commander, Grand Cherokee – $5000

2009 Jeep Compass, Patriot, Liberty, Wrangler – $3000

2009 Mercury Grand Marquis, Milan, Sable – $3500

2009 Hummer H2, H2 SUT – $5000

2009 Saab 9-3, 9-5, 9-7X – $8000

2009 Land Rover Ranger Rover – $9000

2009 Land Rover LR2, LR3, Ranger Rover Sport – $6000

2010 Infiniti EX35, M35, M45, QX56 – $6000

2009 Infiniti F35, FX50, M35, M45 – $6000

2009 Infiniti EX35, G37 – $4000

2009 Lexus LS-450, LS-660L, SC 430 – $10,000

2009 Lexus GS-350, GS-450h, GS-460, LX-570 – $3000

2009 Audi A3, A4, A6, S6, S4, S8, TT - $6000

2009 Audi A5, A8, Q5, Q7 – $5000

2009 Volkswagen CC, Eos, Routan – $6000

2009 Volkswagen New Beetle, Tiguan, Passat – $6000

2009 Volkswagen Jetta, Touareg 2,  GTI – $5000

2010 Volvo C70, S80, V70, XC70 – $4000

2009 Volvo C70, S60, S80, V70, XC70 – $5500

2009 Volvo C30, S40, V50, XC90 – $4000

You can get free price quotes on any of the above vehicles from Edmunds.com.The quotes will automatically include any cash-back rebates or discounts that are currently available.

Lexus

For May 2009, there is a $1000 rebate on the Lexus ES350 — but only to loyal customers who now have an ES350 and have it financed or leased through Lexus’ fianance company. Talk about playing hard to get.

There’s also a good 2.9% APR loan deal (good until 6/1/2009) on the Lexus ES350, IS250, and IS350 — but only for 60 month loans. And only for people with good credit. Talk about playing even harder to get.

However, there are two other, potentially more interesting, deals on the Lexus RX350 SUV and RX400h hybrid. On both these vehicles there is a hidden factory-to-dealer rebate of $5000 and $6000 respectively. This means the dealer can share some or all that money with customers as a nice price discount without making it obvious that the vehicles are being generally discounted. If the dealer is overstocked with these vehicles, you can be assured you can get most of that money.

In summary, Lexus buyers don’t often get manufacturer incentives but, it happens occasionally. Of course, customers can negotiate prices discounts that come directly from the dealer. Lexus has one of the highest profit margins built into their MSRP prices of any brand. Dealers have a lot of “wiggle room” — although they also have a lot of business expense and overhead to pay for those nice showrooms, free cookies and coffee in the nice service waiting room, and so on.

You can get free price quotes on any of the above cars from Edmunds.com. The quotes will automatically include any cash-back rebates or discounts that are currently available.