Quality food is available at an affordable price in Sydney; even well presented, nutritious and quite filling food.
For an amazing lunch at just around $20 a pop (for a late lunch, may not need to worry about dinner) then you can't go past Fundamental Food at Darling Street Balmain. Great ambience and service; funky and trendy. A word of warning: this establishment does get busy. You will be lucky to get a great outdoor table, otherwise the booths inside are just as great. Extremely fresh vegetables. Love their burgers with chips, and a drink is also included in addition to a complimentary jug of water. I really, really like it.
Otherwise for amazing water views along Cockle Bay Wharf, fast service and cheap eats for Dinner, then Blackbird Cafe is worth coming to. Not an establishment you would want to go to for any special occasions, however a great casual, laid back, friendly and fairly cheap dinner hot spot. On Monday night, if you come before 6pm, a supreme pizza will only set you back around $7. Love it. And happy hour at the bar just compliments the fresh and well presented pizzas.
Otherwise if steak is more of your thing; for only $10 a pop you can't go wrong with a chunky well done New York style steak at the St James Hotel. Lookout for the Cat and Fiddle and Dick's hotels in Balmain, and you will be in heaven with cheap and quality chicken schnitzels or parmas with salad and chips, and not to mention fast, friendly service and music to boot. Sometimes it just seems like a waste of time and energy to cook at home.
I think the New York Restaurant in the Cross still exists. Set amongst the brothels this place is straight out of the 60's. Mains from $6, desserts from $3. You get a complimentary slice of bread with every main and you can BYO or they sell a choice of lemon or orange cordial. Your fellow diners will likely be a colourful bunch from both ends of the economic stream.