We stayed this summer at the Courtyard you posted. We had a good package deal that included a full breakfast. We did have to pay for parking (it wasn't $30, I want to say $15??) It is up the hill from the falls, about a 10-15 minute walk.
I'd be iffy going this time of the year. I'm not sure (?) if they close up the Maid of the Mist boats, but I'd surely not want to be on it getting wet in the cold. Likewise, Journey Behind the Falls (Canadian alternative to Cave of the Winds) is a soggy attraction. (They give you flimsy plastic raincoats but you still get soaked.)
A budget way to see the sights is the Can.. Parks Pass (I think it was Great Gorge Pass). It covers Maid of the Mist, Journey Behind the Falls, a how the falls was made movie (not that exciting, but interesting), the walk along the Niagara rapids and bus service for 2 days. (Several bus stops along the way to stop at, again, about 10 minutes walk from that hotel.) You also get 1/2 off for several other attractions- we only did the whirlpool aerocar, but that was neat (and only like $4).
Get the pass at a AAA office before you go, it's even less expensive!
I don't know that things were necessarily any more expensive than any other touristy area/city. Our hotel included a full breakfast, so we did snacks/light lunch things at a snack bar, then usually drove out of the downtown area (toward Lundy Lane) for suppers. The usual array of fast food/etc places out there that weren't a mint. The Flying Saucer restaurant is fun. They have have an inexpensive breakfast, but were average priced for supper. Unique/fun at any rate.
We also liked Oh Canada, Eh, which is a corny as heck dinner show. It's close to $50 per person, so not budget
except if you book online (we did it same day), children under 16 are free! Made it certainly worthwhile for dinner and a show. It's hokey as all get out, but even my 13 year old DS liked it, which is a plus for me!
