500 pounds a month?I dont think so.I am single and my monthly bills,i.e. electric,gas,phone,internet,water and dijiturk average 300tl add to that the possibility of SGK payment(200tl per person)food,travel,rent or bills attached to ownership,pet food if you have animals and day to day living expenses.You will probably want to socialise and when friends come over to visit,entertain them.Add to that fares back to the UK whether revisiting or on an emergency basis and any medical expenses whilst living here.
I dont intend to discourage you as the advantages of living here greatly outweigh the disadvantages,certainly for me,but you need to bear in mind all these factors before you decide to move over here permanently.