As posted above Mousesavers lists any discounts. I know right now Orbitz (I think, might be Expedia) is running 15% off through the rest of the year. It's posted on Mousesavers if you want to check the exact info.
I think where the DLR hotels are so expensive when we travel there next fall, we will probably do a split stay: 4 nights off property and 4 nights on. I priced out all three for 8 nights next fall and it ranged from $2797 for Paradise Pier standard room all the way up to $4313 for Grand Californian. Those prices are insane when you figure you have to add in tickets, flights, food, etc.... Split stay for us is the way to go!