So riding the bus in Costa Rica is cheap and it’ll take you anywhere. The problem is figuring out when the bus is going to be running.
In the bigger cities this doesn’t appear to be a problem, if you miss a bus another one will be by soon and if it’s not the right bus it’s still heading in the correct direction, just hop on. In the more remote areas (such as Montezuma) they probably don’t come more than every two hours so if you miss the bus it’s a pain.
The people closest to the bus stop seem to have the most reliable information. Restaurants and internet cafes have it written down, but they wrote it down ages ago. My trickiest problem is asking “when is the next bus?” and they tell me “it’s in 20 minutes” but that’s too soon for me so I try to find out about the bus after that and it’s no good; I have to come back in 25 minutes and ask again to get the info for the bus after that :)
The appears to be no schedule posted, even at the bus station in Cobano (a central town in the lower Nicoya Peninsula). I did notice the bus that goes from Montezuma to Cabuya to the National Reserve does have a schedule taped to the window (4 trips a day) with pricing and everything; as an added bonus, it generally seemed to be leaving Montezuma at the correct time! More info below.
Pricing is cheap though. In San Jose I took a bus for about 150 colones (28 cents) but honestly I don’t know far that would have taken me, it was in front of me heading the right way and it kept going once I got off. In Montezuma, it’s 300 colones (55 cents) to go to Cobano which is 7 km. away (a very hilly/dusty walk).
You can get a direct bus all the way to San Jose from Montezuma, but you might not get a seat and there isn’t any A/C but I think you can do it for about $8-ish (maybe $10 including the ferry ride). CORRECTION: The direct bus does have air conditioning; if the directo bus in Montezuma does not have A/C, when you switch onto the directo in Cobano that one has A/C (and little controllable vents like on an airplane), I’ve taken it three different times now and it is an excellent value (it seems like it will stop at the SJO Airport [you must ask/tell them!] or San Jose at the Coca Cola bus terminal (updated March 2012; I think I paid just under $14 and that included the ferry ride). Montezuma to Cabuya to the National Reserve info: When I saw the schedule it said 600 colones to the Reserva and 500 colones to Cabuya (just over or under a $1.00). It leaves Cabuya for Montezuma at 7:20 am, 9:20 am, 1:20 pm and 3:20 pm (not sure what time it actually leaves the park). It leaves Montezuma for Cabuya at 8 am, 10 am, 2 pm and 4 pm. Obviously they get a long lunch hour or maybe it doubles as a school bus? (These times and prices are from November 2008).