January is a good time to visit WDW, except for the MLK holiday weekend. We were there for my son's school trip around the 10th this year and other than the Marathon activity on the weekend, it was very quiet. February is good too, except for President's Day week when a lot of New England schools are on winter break. The only issue is that it's too cool to swim and the water rides like Splash Mtn and Kali River Rapids are closed in January for upkeep.
And as for deals, I think I only paid about $69/night for the All-Star Sports with a military rate, but the general discount wasn't much more.