If you want to see Venice but don't fancy the cramped and overpriced accommodation on offer, just look what you can get in Padua, 20 minutes train ride away. An airy two room apartment, very well equipped, at a modest price. And you may just fall in love with Padua itself, a beautiful early Renaissance town, with piazzas and churches to explore, free of the massive tourist groups that swarm through the major tourist centres.
The appartments are in the University quarter, ten minutes stroll from the town centre, and with several very nice cafes and bars nearby.
One drawback is that these attract some pretty boisterous customers and there's a lot of raucous celebration late at night. But night shouting seems to be an Italian thing - we encountered it in Florence as well.