I'm not sure if there is a specific % you can go by. Most deals (I believe) have gone with "no haggle" pricing where they have the price (some amount below MSRP) and they don't usually haggle over price.
If I were you, I'd get a quote from either (or both of the following) with what model and options you are looking for:
http://www.thervexpress.com/
http://www.rvdirect.com/
This should give you about the lowest price you're likely going to find, I believe. I'm not sure how many dealers will match or beat the price from these on-line rv dealers but it's worth a shot. Some may not because they like the high margin they usually get or because they just don't get enough of a price break from Jayco due to low volume of sales, or so I assume. I really don't know.
I bought my RV using thervexpress.
- Justin
__________________
-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Jayco Jayfeather 2012 X20E
-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+