Penas Blancas, Nicaragua
Border name: Penas Blancas
Closest major cities: San Juan del Sur, Nicaragua and La Cruz, Costa Rica
Cost to exit Nicaragua: C$67 Cordobas ($3 USD) per person ($1USD tax, $2USD for the stamp)
Cost to enter Costa Rica: $0. (For Americans and South Africans)
Cost for vehicle permit: CR$2175 colones ($4.50 USD) fumigation, CR$8365 colones ($17 USD) insurance
Total time with a vehicle: 2 hours
Date crossed: Saturday, April 23, 2012 Easy border crossing, all things considered. Immigration is quick and efficient (as long as you don't get stuck behind a bus load of people). Customs (aduana) on the Costa Rican side is a hassle if you are bringing a car, because there are two separate customs offices about 500 meters apart.
If you are heading from Nicaragua to Costa Rica, don't trust the friendly strangers who offer to help you through the process. They are there to take advantage of travelers who speak poor Spanish. They offer to talk to the people at the border for you. At first they don't ask for anything, but after they build your trust they ask for money and your passport to do some part of the process for you. They return with your passport and you move on. Eventually you finish the border crossing process, them asking for a little money at a time until you are almost broke. They do point you in the right direction, which makes them believable, but it shouldn't cost you more than a few bucks to cross.
From Managua take a public bus to Penas Blancas (border town). Leave the gated area and head to the white buildings to get your exit stamp and pay the 2$ exit fee and fill out custom form. Once paid go back out and walk down the road ~500m-1km to Costa Rica side. Try to avoid currency exchange people or young men acting as guides. Police will likely ask to check your bag. Costa Rica has no entry or exit fees but does require customs form. Go into the white building in the line marked entry. Once finished local buses leave out back side where ladies sell tix for local buses. Tica bus is also available from SJ or Liberia or Managua and will walk you through the process if you go with them.