I am wanting to travel to canada from australia very soon n would appreciate a little information n help...?

so i am planning on traveling to canada from australia in august of this year (vancouver to be precise) n as i have decided this rather last minute, i think my best bet at arriving when i want to would be to enter the country as a tourist as apparently i can do so easily n without a visa for a stay of up to three months. i am wanting advice on whether or not it is possible for me to apply for a working visa once i am in canada, how easy or difficult this would be to do n if it is within reach, how exactly would i go about such. i am also curious as to about how much money the average person would need to survive under "normal" circumstances per week so as to estimate a budget. this can be including rent or not. any rough guide will be appreciated. thank you in advance :)