San Jose is one of the more expensive cities in Central America, though it’s still fairly cheap by North American or European standards. Most people just fly into the capital and then move on to one of the beach cities or La Fortuna for the volcano, but San Jose itself is worth a look around for a day or two.
Food and drinks are quite reasonable in price, especially if you speak some Spanish and go to places where the locals eat rather than the restaurants aimed at English speaking tourists.
Once you start looking for things like canopy tours and other adventure activities, things are usually priced in US dollars and prices can be higher than you might think for this region.