The choice here is depends on your specific requirements and opportunities. You are buying something almost completed or under construction on the middle stage, or on the pre-sale when the project even not started yet, in this case the buyer can get the cheapest price, and will need to wait about 2-3 years until the project will be completed, but at the same time you receive interest-free payment by the installments for the whole period of construction.
If you interested in the secondary market of real estate and you want to buy something ready, in this case you have to pay full amount at once. After you find the right property, you have to pay booking deposit during signing of the contract, which is usually 10% from the selling price, but this amount always discussable. Then, after all the documents for the transfer is ready, transaction should be held in the Land Office, where the buyer will get Chanote (Title Deed) with his personal name and the seller will get the rest amount in the same time. Usually the deal takes from 4 working days to 3 weeks.