The "average" price is 4% off invoice, most local dealers will be at invoice or 1% below (usually), so you'll need to negotiate. The best deals available are from the Texas group buy at 5.5%, and the DC group buy at 7% + $500 fee (6% net).
See here for invoice pricing, you can do the calculations. Remember to add the $995 destination fee AFTER figuring the price.
2014 Grand Cherokee - Ordering Information and Pricing
For a 14' Overland Diesel 4x4 with ORAII you're looking at the following (including destination, no TTL):
4% off - $47,959
5.5% off - $47,225
6% off - $46,980
That said, it looks like the offer at $48k is right at 4% below invoice, which is a good deal (IMO).