See if someone you know works at company that buys dells. If so you may be able to get a discount on a Lattitude via the employee purchase program. Somewhere around 20% discount seems to be about average. Also, you can check the outlet, some deals there.
The Latitude line is geared toward the corporate side. These laptop computers are usually leased. Based on this fact you most likely will not find too many discounts on this series nor the Precision laptop computer line. The reason for this is that a large company charged a lease based on a $3000 laptop that is selling for $2000 with an online coupon wouldn't go over well with many executives.
Once in blue moon there will be a general use coupon good on lattitudes. I got my Precision M70 (same chasis as lattitude D810) using such a blue moon 35% off coupon. Saved me a bundle.
If you can't wait for the next blue moon you need to get to the dell small business web site and sign up for their email news letter and their snail mail catalogue. Do it with several accounts if you can.
Also if you have EPP do the same for their mailing list.
About once or twice a month you'll get an email with a "one time use" perecent off coupon not every time but once in a while there will be 20% off or so on the lattitudes.
I signed up for Dells Small Business Coupons and got a 10% off emailed to me....Once I got te coupon I tried to order a d610 that was already on sale online and when it would not take the coupon code I called dell and the guy that took my order was really nice. He said that the coupons are not good with any other offer but he would see what he could do. He put me on hold and when he came back he took another $150 the system that was already $300 off. (So I ordered 2 of them) lol....one for my friend which is why we were calling in the first place and one for me.....which I love.
Good Luck and here is the link to dells coupons.