Base on my experience as an agent here in the Philippines, the agent will get a commission of 5% from the total amount price of flat.
... but it's not the Philippines.
An agent here will charge anything from 1/2% - 2%, with 1 1/4% or 1 1/2% being the norm.
The money will only be paid AFTER completion, and usually via the seller's solicitor after their receipt of a valid invoice.
