Many restaurants and grocery stores are slightly less expensive in Costa Rica than in the United States, but like most places, you get what you pay for.
Food and Dining Out
Keep in mind that most hotels offer a complimentary breakfast.
If you eat breakfast out, a typical small restaurant (called a "soda") will serve you rice and beans, eggs, and coffee/juice for about $3-5. You can expect a lunch or dinner to cost around $5-7. Costa Rica's staple meal is called a casado, and it includes rice, beans, salad, meat, maybe some plantains, and a savory sauce.
For a change of pace, you can find pizza, pasta, and steak in both typical and international restaurants. Top destinations (like Arenal, Monteverde, and Tamarindo) always have plenty of options catering to international travelers. These meals will range in price from $8-15 per person. High-end restaurants have prices comparable to those in the United States.
Remember that the price of meals can vary quite a bit depending on your location. You can expect to pay less for restaurants in rural areas, and quite a bit more in popular beach towns like Tamarindo and Playa del Coco. When you're visiting these destinations you should budget to spend as much as you would in a beach town in the U.S.
Beer or mixed drinks are about $2 - 4 at restaurants or typical bars. In fancy hotels or upscale restaurants, drinks can be 2 to 3 times as much.
Water is about $1 for a 20 oz bottle and $1.75 for a 60 oz bottle, while sodas and juices are similar to U.S. prices.
Taxi rides are reasonably priced, and cost between $1-1.50 per kilometer.
Shopping and Souvenirs
T-shirts are around $10, and bags of coffee usually cost $7. Souvenir shops near the Costa Rica's top beaches have prices similar to those in the U.S.