There are some "agencies" only charging 50tl per person. I have not used them so can't comment on 1st hand experience but believe them to add a small fee for "extras" such as photocopying etc. to the final bill. I used Carole & Tayfun, residency done within 2 weeks, total cost 500tl for 3 years which has to work out cheaper than hopping back & forward to Meis or similar every 90 days. For me the best bit is it avoids the dreaded scrum for a Visa at Dalaman when arriving back into the country, that in itself has to weigh heavily for getting residency.