Hi
I've seen a second hand i7 3770k with a Asus Maximus V gene and a antec kuhler H2O 620 with 16 GB of ram for 350 euro's
But new you can get a i5 4690k and a Gigabyte GA-Z97X-gaming 3 for 350 euro's.
What would be better for Gaming and doing a lot of online work (writing, watching youtube...