Throughout Costa Rica like in many other Latin American countries there are different local markets you can find, some with souvenirs/goodies and others with different meats/fishes.
I never buy souvenirs at large stores, I prefer going to the markets and feel like I’m contributing to the country’s locals although sometimes those locals might originate from neighboring countries. Knowing that there were finding a market would be easy I decided to leave the souvenir shopping for right before I left; sometimes I like to get something different from every part of a country but this would’ve meant carrying more luggage throughout the trip.
The market in San Jose is a mix of establishments selling souvenirs, household items, massages, food, fish and meats. You can bargain here the way you can at almost any market but keep in mind things can be slightly more expensive like San José is one of the largest touristic hubs in the country. You should also walk around to other stores and see their pricing before you begin to negotiate to make sure you’re truly getting a good deal. There are plenty of stores to choose from so if you do decide to check it out for souvenirs it’ll be easy to find items for all of your friends.