The Turkishtravels.info blog has outlined the last bus times of the summer season.

They are:

Numbers 1 or 3
Ormankampı > Altınkum = 1:00am
Altınkum > Ormankampı = 2:00am

Number 6
Mavişehir > Altınkum via Sağtur = 12:00am
Altınkum > Mavişehir via Sağtur = 1.00am 

Number 2
Mavişehir > Altınkum via Kardelen = 12:00am
Altınkum > Mavişehir via Kardelen = 1:00am

Number 4
Yeşilkent = 1:00am

Aquasis Hotel = 1:00am

Bus prices have increased. They are as follows:

ALTINKUM > MAVİŞEHİR / MAVİŞEHİR > ALTINKUM: 3TL up from 2.25TL

MAVİŞEHİR > YEŞİLKENT / YEŞİLKENT > MAVİŞEHİR: 3.25TL up from 2.50TL

STANDARD FARE: 2.50TL up from 2TL (MAVİŞEHİR > DİDİM / DİDİM > ALTINKUM etc)