What should I budget to travel for a year mostly in South America but also a little bit in USA and Canada.?

I'm a light traveler, with only a backpack and I tend to stay in hostels and wherever is cheapest. I'm considering bringing a tent but I'm not sure (any suggestions?) and I'll probably use public transport for most of the way. The basis of the trip is Alaska to Argentina.

I was thinking $2500US a month. But really I have no idea so any suggestions would help.

firstly 'i'm so jealous' good on ya!!
I travelled through Canada and the States. It's so simple to camp in the states and it's cheap. Depending on time of year camping in Canada can be cold but it's def doable. I't's alot more expensive in Canada than the US. There's not alot of hostels in the US which makes it difficult but there are def cheap hotels. The IS is vast so you'll probably be doing alot on the greyhound. We bought a car in Canada for $1500CAD and that took us all over. So much fun and we stopped were we wanted (which made camping easy).
Have fun whatever you!!!