If you do not want to buy a property for sale in Costa Rica but rent for a while and get a feel for the market then you can safely budget on around 1500 US dollars per month. You can rent a nice fully furnished home in a quiet area for an average of $400. This would be for an average home by US standards but the $1500 would allow some eating out, traveling and food costs.
A good strategy taken by many couples relocating to Costa Rica is to move to an area and rent for a while. Get to know the lay of the land, local prices and be on hand to buy up and bargain. Then buy a piece of land or property to live in. You could realize a return on this investment by building some cabanas to rent to visiting tourists. This can also be a nice way to keep busy.
As a price guide you can buy a lovely two bedroomed house for sale in Dominical for as little as 225,000 US dollars. For this you get a 2 bedroomed and 2 bathroomed property all ready to go. The house has no pool but amazing views across the mountains and out to sea. Plot size is generous at over 3,000 square meters and house size is again a very generous 1500 meters squared. With such a plot it would be easy to build a few cabanas and rent these out to traveling surfers.
Food prices in Costa Rica depend on your own preferences. Buying locally can safe a fortune over expensive imported products, and on the whole is much healthier. Restaurant prices are around $15 per head for a nice meal with wine.
As a general rule of thumb local produce and labour costs are lower but imported products much higher. Medical care is low and of a high level.