For a cheap meal you will find stalls at the market that sell all types of food, including eggs, noodles, chicken, squid. Just ask for anything you may fancy and the stall holder will just put it in a plastic bag for you, but add your own sauces.
Try eating a typical burmese breakfast from one of the many restaurants that open early. Order the curried veg and chapatis served with a pot of tea. The chapatis are flung into a clay oven where they stick to the wall for a few seconds then taken out and served to you with your curry. Tastes delicious and costs next to nothing. We found a tea house serving breakfast very near the bridge. Once you cross the bridge turn left at the major intersection, walk another 200m or so and you will find this tea house on the left. The owner/ staff were very eager to talk to us.
There are many food carts around town where locals are selling snack food. Don't be afraid, try the tasty treats.