The various hotels always have really good packages available. The last time we went, we paid somewhere around $200 for a package at the Falls View Marriott--just as the name indicates, the rooms have a view of the horseshoe portion of the falls. There's a vent in the room that you can open to hear the falls, too! Anyway, our package included two nights in the Marriott, two buffet breakfasts for two, and a $50 voucher towards dinner one night (all food deals are for their on-site restaurant which isn't bad). Free shuttle to the casino and a couple of other perks were thrown in, too. We figured that after all the free food etc our room cost us about $25 a night! We stayed there twice on this type of package--once when we were there for laser eye surgery, and another time just for fun. (The very first sight I saw when I woke up after my post-laser-surgery nap was Niagara Falls--something I will always vividly remember!).
If you call the hotels there directly you can get info on the packages. The main Marriott number may not be helpful for the package deal. Now that so many new hotels have gone up around the casino, the competition can be pretty fierce among them especially for non-prime time.
As an alternative, there was a Comfort Inn right across the parking lot from the Marriott--no view, no perks, but a nice indoor pool and cheap as can be, under $40 a night with a AAA discount last time we were in the area.