Do I have to buy minecraft to use commands?

I'm able to play minecraft without purchasing it and I'm able to use some commands but i'm not able to use most commands, it says command unknown. Is this because I haven't bought the game on the computer?

ShanontheBrave

Depends. If it's basic commands that don't work like /gamemode 2 then you do need to buy minecraft, but if it is more complex commands like bind <KEYCODE> <COMMAND> {PARAMETERS} then you need to buy it an download single player commands.