Discount Calling Rate

Which Turkish prepay SIM provider works best for a 3 week trip to NE Turkey? Avea? Vodaphone? or Turkcell? I am only interested in LOCAL SMS (to other Turkish mobiles), and the occasional call (only to Turkish numbers). I don’t need roaming, or international calling services? Which provider has lower rates, no setup fee, or is most common?

Thanks

Desiree