Is the 30 Euros per car or per person, typical cost of transfers around this time of year are usually between £60-£70 per car but is changing quite a bit because of the increasing price of fuel!
In terms of a hire car, if you go to a reputable company, and there are lots of them, (just search function here on the forum for tips), you will pay £25 ish per day so the choice is yours. Part of the fun of visiting Turkey is to get out and about so a car gives you that freedom but the public transport is also great, cheap and is part of the experience.
Good luck
Kevin