I can't really help about accomodation in Venice, as I live 1 1/2 hour away
and slept in the city only once more than 20 years ago, but I suggest you
to check both the price and the location.
Some less expensive hotels can be out of hand, if you wish to stay in the
heart of things; cheaper accomodations can be found on mainland in Mestre
but this involves a 15' bus trip back and forth. I'd also avoid a hotel
onlooking a minor canal: it's romantic indeed, but also very damp and
sometimes the water stinks...
Sorry, didn't want to spoil the Venice magic but hard reality sometimes
slap you in the face.