How much did you spend on your South American backpacking trip?

I've got about $4,500 saved up after gear, vaccinations, and airfare are paid. I'll be spending about 100 days going through Venezuela, Colombia, Ecuador, Peru, Bolivia and Argentina. Obviously, I'll be staying in budget hostels, eating cheaply, taking buses, etc, but I will be hiking Macchu Picchu and doing some excursions (not Galapagos or Angel Falls...dang). Have you taken a similar trip? How much did you spend? Thanks.