Are you talking about getting it under invoice, or under the price on the sticker on the window?
If you are talking about the sticker on the window the MSRP (manufacturers suggested retail price), yes, you should get it for a lot less than that. Thousands less.
If you are talking INVOICE, hard to say. Best thing to do is to get a print out of the wholesale price from Consumer Reports. That is the price the dealer will have paid for it AFTER selling it. They get 3 or 4 % of the INVOICE price back from the manufacturer when they actually sell it. And sometimes, there are other cash kick backs or incentives.
A dealer can sell a vehicle for less than MSRP, and less than DEALER INVOICE, and still make a profit, as long as the price you pay is above the WHOLESALE price.