The general custom is for the Buyer and Seller to share equally in the closing costs. This can be modified by agreement and usually depends upon the particular transaction like motivations and negotiations. As a quick calculation, you can assume that the closing fees are about 4% total so the purchaser and seller will each pay 2% based on the purchase price.
There are 3 basic fees, here are more details:
1.) Notary fees
Closing costs containing the notary fees are, based on the real sales price, 1.5% from the first one million Colones, the local currency, and 1.25% on the balance. If you simply calculate 1.25% based on the purchase price for the notary fees you have a good estimate.
2.) Transfer Tax
Each transfer for a property requires paying a one-time transfer tax which is about 2.5% of the price. This includes several minor fees and stamps required.
3.) Escrow Service
Escrow or Fideicomiso helps you as an independent third-party entity to hold the money till closing. They also can help the purchaser to provide all the documents required by the new money laundering laws and also to the seller for the proof of funds when he receives the money out of Escrow into his account. Such Escrow services starting at about US$500 depending on the amount of the transaction and which company will be used. Make sure the Escrow is reliable and registered by SUGEF the Governmental controlling institution when Escrow is done in Costa Rica.
Of course, there might be some additional fees for the Seller like capital gain tax and the sales commissions.
The ABC team can help and give you a quick estimate based on the property you have in mind buying or the one you are selling.