Since I have been in Turkey and that is over 20 years, (I lost count after that... maybe 2 or 3 more) it has always been the case that Agents charge at both ends, either for buying or renting. When you go to an agent here, you are using their expertise and local knowledge and that as a buyer is what you pay for and if you get the right agent invaluable. As a seller you pay for the marketing of a property. It doesn't matter if you are Turkish or a Foreigner you pay the 3% at both ends. Or you do where I work!!
As Scunner says, the Agent in Turkey does all the conveyance work, negating the need for a Solicitor, however if a buyer feels they need a Solicitor then we as agents are usually happy to work with them. At our company before we advertise the property, we do a preliminary search, make sure it is unemcumbered and in an area where a Foreign person can buy, and if not we advertise the fact.
After the offer is accepted on a property, we draw up contracts, take buyers to the Notary and help with Tax numbers and Bank accounts. After the sale, we then get the utilities transferred and also if the client needs help with small things we are there, so I think that is worth paying for.
As Scunner says, agents are there for the customer for years to come, most of our customers go on to do Maintenance contracts with us and as is happening more now, we are selling properties for people who were once buyers with us.
If you had told me 20 years ago I would be an estate agent, I would have laughed my bits off, however here in Turkey I have it in the most part a rewarding job.