Many restaurants aren't open for breakfast. Those that do (mostly fast-food and diners), serve eggs, toast, pancakes, cereals, coffee, etc. Most restaurants stop serving breakfast between 10 and 11 AM, but some, especially diners, will serve breakfast all day. As an alternative to a restaurant breakfast, one can grab breakfast food such as doughnuts, muffins, fruits, coffee, and packaged drinks at almost any gas station or convenience store. Coffee shops (of which Starbucks is the most well-known) are popular for breakfast; although they offer pastries and other items, most people frequent them for a morning dose of caffeine. Some chains, like Dunkin' Donuts or Einstein Brothers Bagels, are sometimes liked more for their coffee than their actual food.
Continental Breakfast is a term primarily used by hotels and motels to describe a cold breakfast offering of cereal, breads, muffins, fruit, etc. Milk, fruit juices, hot coffee and tea are the typical beverages. There is usually a toaster for your bread. This is a quick, cheap (usually free) way of getting morning food.
Lunch can be a good way to get food from a restaurant whose dinners are out of your price range.
Dinner, the main meal. Depending on culture, region, and personal preference, is usually enjoyed between 5 and 9pm. Most restaurants will be willing to box up your leftover food (typically referred to as a "to go box"). Making reservations in advance is a good idea if the restaurant is popular, "up-scale", or you are dining in a large group.
Buffets are generally a cheap way to get a large amount of food. For a single, flat, rate, you can have as many servings of whatever foods are set out. However, since food can be sitting out in the heat for hours, the quality can suffer. Generally, buffets serve American or Chinese-American cuisine.
Many restaurants serve Sunday brunch, served morning through early afternoon, with both breakfast and lunch items. There is often a buffet. Like most other meals, quality and price can vary by restaurant.