Hi,
I travelled through Mexico last October for 3 weeks. I stayed in Cancun for 4 nights as I was flying back from there. I stayed in the "Avalon Baccara Exclusive Hotel", which I found to be excellent value. Note, not the Avalon Grand which is next door and much larger. I think it was around €28 per night per person (there were 2 of us). We booked last minute while we were in Mexico, and were not all-inclusive. Hotels tend to not be as helpful/nice when all-inclusive since they know all your stuff is already paid for.
We were there during hurricane season (as you will be), hence the good prices. Its very expensive at the peak times. It's a small hotel, 28 rooms, with swimming pool & beach access. Our room contained its own jacuzzi as well. The hotel is on the main strip of hotels, close to major shopping centre (walking distance), with all major shop, restaurants etc, at good prices too.
Hope this helps