How much cash should I bring on my trek?

You will need cash for food, lodging, snacks, transportation, and tips for your guide and porter. Figure a minimum of $25-30 a day for food and lodging more if you want to drink beer, eat meat, or buy other luxury items. The estimated transportation cost can be found on the itinerary, don't forget to factor in tickets for your guide or porter. For tips, equivalent of $2-$4 USD per day per person is good for a guide if there are multiple people; if only one person, then the equivalent of $3-$5 USD per day. For a porter the equivalent of $3-$4 per day total (between all the people using the porter), or if one person has hired a porter the equivalent of $2-$4 USD per day. Then add some extra since better to have too much than run out.