Scanned this thread and have a simple answer really.
In Turkey the general rule with regard to Estate Agents is 3% from the vendor 3% from the buyer. This is standard, this is not something that is practised in this area only it applies to Turkish buyers too.
With regard to private sales, if you have been introduced to a property via an agent, you are expected to pay a fee, if you see a property in an advert directly from the vendor, make an appointment direct with the vendor, then no fee is applicable.
Also, having worked in the UK for many years within Estate Agency, we used to charge 2% sole agency and 3% multi agency. I know that nowadays there is more leeway in the agency fees, but, as a general rule the property prices in the UK are much higher than here.