Today in the "ferria" (farmers' market) where I live, besides the usual piles of year-round fruits like pineapples, papayas, citrus, bananas, etc., I saw some nice sapotes Columbiano, japlums, nice selection of W. Indian type avocados (cheap!), still lots of mangoes, jocotes, mamon Chinos, guanabana. Next week there'll be others I'm sure. If you're going to Jaco you'll probably pass through Orotina which is the avocado and mango center of the country. Zill's Nursery in in that area.