Costa Rica isn't known for it's culinary prowess, so expect simple local cuisine - gallo pinto! - mixed with a healthy amount of high-priced tourist options.
Whatever you do, be sure to douse your rice and beans in Costa Rica's own Lizano Salsa. Seriously, this stuff is from Heaven (read the Amazon reviews if you don't believe me).
For the most part, any restaurant you find along the road the Manuel Antonio will be priced similarly to the US, so keep that in mind before pocketing your Colones. When you do venture up the hill, head toward Cantina Salsipuedes for a few guaro sours and one of the best tuna poke dishes I've ever tasted.
Down the hill in Quepos, explore the market in the center of town before bellying up to the ceviche bar. It's not fancy, but for $5 you'll dine on some super tasty fish and shrimp - I think their secret ingredient might be lemon lime soda, but nonetheless it's delish.
Load up on lots of fresh pineapple, mango and coconut at any of the fruit stands and keep these on hand to blend with ice & rum. It's by far my preferred way to drink poolside.
Give yourself plenty of time to kick it by the pool or ocean and catch up on your reading. I made it through three books in a week! Total bliss.
When you are finally able to tear yourself away from sunbathing, hike through Manuel Antonio National Park. Park admission costs $12 - be sure it buy it from the Coopealianza office - and it well worth it for a gorgeous hike through the rainforest! You'll definitely see monkeys, hermit crabs and a plethora of birds. Wear your bathing suit and hike to one of the park's four pristine beaches, all of which look like something out of another world.
Also worth checking out is the farmer's market which happens every Friday evening and Saturday morning in Quepos. Loads of beautiful fresh fruits and vegetables as well as locally crafted goods, coffee and ice cold coconut water. The market also happens to be next to the water which means incredible views while you shop.
We lucked out in finding the Villa Malinche on Airbnb (duh, where else). Tucked away at the top of a hill and out of the touristy part of town, the space was perfectly secluded and just enough off the grid.