Steam provides Grand Theft Auto Complete Pack at 9,99 euros only for a few hours. The collection includes GTA, GTA2, GTA3, GTA Sand Andreas, GTA Vice City, GTA IV and GTA Episodes From Lliberty City.
GTA San Andreas is still available on the Mac App Store for 5,79 euros, however comments report very deceiving performance even on fastest macs. The PC Steam version under Crossover Games (see compatibility list here) may then run faster. About GTA IV (also supported through Crossover however still requiring high resources on Windows), using Bootcamp may be better.
We can also found on Steam Deux Ex : Human Revolutions at 24,99 euros (50 percent discount).