You can either buy Arma 2: Combined Operations. Buy Arma 2: Operation Arrowhead and Arma 2 Free. Or you can pirate Arma 2: Combined Operations. The DayZ mod itself is free. I suggest using SixLauncher or DayZ Commander to install.
To hack on BattlEye enabled servers, you need a BattlEye bypass. There aren't any undectected free bypasses at the moment. VA is the most popular bypass. It's about $8 a month. To actually have "hacks" or "scripts" you'd need a decent menu. infiSTAR's menu is pretty popular at the moment.
Expect a ban within 1-4 days thought. I'd say get @
Bosegelucke 's life time key service.