The cheap way to get great local food in Portland is at food carts. This is no mere turnpike cure for alcohol poisoning. I've counted three parking lots so far where food carts pay rent, setting themselves up semi-permanently.
The carts are also regularly inspected by the health department so you don't have to worry about foodborne illness every time you want a gyro.
My favorite so far is Brunch Box, which has breakfast sandwiches on homemade English muffins.
So now, thanks to the fine, fine folks at Disjecta and Willamette Week, there is a Food Cart Festival. Next weekend, you can sample wares from a swath of carts for the grand whopping total of $5. Yes, that includes the food.