New Vegan Attempt.

[wishformore]

Ok, I've tried to go vegan before, but everytime I've failed b/c I inadequately prepared and found myself out and about in situations with nothing acceptable to eat. Plus my family thinks it's the most ridiculous thing ever, so they deliberately attempt to sabotage me. (I don't visit often, perhaps it's their way of getting back at me) But, blah blah blah... here's my real question: In order to successfully start this lifestyle and not crash and burn by the end of the first week- what do you all recommend I stock up on?
My only issues are that I am:
a) Poor
and
b) Highly calorie concious.

Any tips you can offer would be greatly appreciated!