My husband and I have practially had an AP to Disney since we where married, we usually buy one every year when we go down. This last time in January we payed $49 a night, $30 off the regular rack rate.
Unfortunatly due to more people coming to Disney and Disney having more people willing to pay rack rates there doesn't seem to be as good as discounts as their used to be (I remember paying $89 for a Moderate in June!)
You will usually get a better discount if you go during a slower time, value season/regular season. It seems Disney isn't giving a discount if you stay during a busy season such as easter any longer.
I would recommend keeping up with MouseSavers.com they always publish AP rates.
Deluxes tend to offer discounts about $100 off, Values are usually about $20-30 off, and Moderates are usually about $30-40 off. These are approximates based off discounts in the past, so they may change.
Jennifer