Hello Dido
I have not been on this tour but I have been on 8 others..
I work on the lines of I might never go to that country again so if there is something I fancy doing then I do it. So work in the cost of anything and everything you might send money on for the optional extra bits. Then have a good look at what is in the price, breakfast,lunches, dinners etc?..then work out how much you will send on food per day x how many days..
I am not a big sender on tourist memorabilia so I don't have a big budget for shopping..
I always take a card with me that I can use while away if need be, do make sure you let the company know your going abroad.
So my answer to your question really is I take as much as I can away as I want to do and see all that is available. Then I put the money I don't use back in the bank when I get home.
When I went to NZ this January I took a large amount with me as I wanted to do many helicopter/lite aircraft flights but due to bad weather above I only managed 1 helicopter flight, so I did bring a lot of money back home.
I hope someone who has been on this tour can give you more of an idea.
Good Luck
Cindy