Most major towns in Costa Rica will have some kind of farmers market, or as it is called in Spanish “La Feria”. In larger cities these farmers markets may be held every day, or multiple times a week. In La Fortuna, it is only open on Fridays. The farmers market is located very close to the center of town. From the bus stop you can see a small bridge, as you cross the bridge the farmers market is immediately on the left in a community hall.
The farmers market opens around 8:30 AM and runs until around 5 PM. However, many places start closing their stalls by mid-afternoon or may sell out of certain popular (especially seasonal) items. Your best bet is to get there between 9 and 11 AM for the best selection. You can get the standard produce like lettuce, tomatoes, peppers, potatoes, etc.
Depending on the season and the vendors there that day you may be able to find more eclectic items as well. There is a gentleman that sells hot sauce that I highly recommend–and he offers free samples if you don’t want to trust my palate. Right inside the door a lady sells these flat wafers that are very tasty and a pack costs about $2. There is a foreign couple that makes baked goods, and sometimes you can get prepared foods like soups and tamales. On occasion there is even someone selling quail eggs.
The owner of the stall on the far left wall has been there for years and has developed a friendship with a local iguana that comes by everyday to eat bananas right off his lap, if you time it right you can get some great shots.
The best part is everything you buy is going to support local farms and it’s often cheaper than the super market. Plus who’d rather give Walmart money than a local farmer anyhow.