One of the best bangs for your buck at Granville island is Kaisereck Deli. For about the same price you'd pay at a hot dog stand, you get some quality food at GI for a lot less than it's neighboring food vendors. For about $4.00, I sometimes just get a European smokie and load up on the sauerkraut.
There's no smell of pan-friend onions to draw you in, but the sight alone will do. It's hard to just walk by the shop without wondering how awesome one of those shiny gourmet sausages would taste. If you're looking for a quick and cheap bite to eat, give it a try. You'll find the staff there pretty friendly, and the food delicious.