Günaydın                   Good Morning

İyi akşamlar               Good evening

İyi geceler                  Good night

The English expressions good evening and good night are singular.  In Turkish they are plural

Merhaba                     

Hello, Hi.  The response to Merhaba  is also   Merahaba

Selam      Hello, Hi but more informal than Merhada

Selamünaleyküm         

Means may Gods peace be upon you, used by Muslims as a greeting.  The reply to this greeting is  Aleykümselam

Allahaısmarladık, Hoşça kalın      Goodbye

The person leaving says Allahaısmarladık or Hoşça kalın      

The person staying behind says  Güle Güle            

Hoşça kalın means stay well

Allahaısmarladık means I leave you to Gods care

Güle Güle means go well

either Allahaısmarladık or Hoşça kalın is correct in informal situations   

Görüşürüz            See you later, the reply is also Görüşürüz

Allah rahatlık versin an informal expression for good night, meaning may God give you peace and comfort.  Generally used by members of the family at home or friends before going to bed.  The reply is Sana da which means same to you to

Hoş geldiniz            Welcome

Hoş bulduk             happy to be here

Teşekkür ederim or Sağ olun         Thank you

Bir şey değil or rica ederim            Your welcome

Gözünüz aydın         When something that the speaker longing for comes true and he tells others about it, they say to him Gözünüz aydın indicating that they share his happiness and are also happy about it, his reply would be  Teşekkür ederim 

Hayırlı olsun         When someone opens a shop or starts a new business, this expression is used to indicate the wish that the new business will bring prosperity and will be profitable.  The reply is Teşekkür ederim 

Güle güle kullan/kullanın         If you buy something such as new clothes, shoes or a car your friends say Güle güle kullan/kullanın to indicate their wish that you use it with joy.  Somethimes Hayırlı olsun is said at such times, the reply for both expressions is Teşekkür ederim 

Afiyet olsun             May there be appetite, pleasantry to someone who is eating or has just finished

Elinize sağlık            Health to your hand, pleasantry to someone who has just cooked you a meal  

Kolay gelsin             May it come easy, pleasantry to someone who is working

İyi yolculuklar/hayırlı yolculuklar     Have a nice journey

İyi tatiller                                     Have a nice holiday

İyi şanşlar                                    Good luck 

İyi eğlenceler                                Have a nice time