I carry a bag with an army of cards. I kinda like to show them off, and in many instances I let my specs pic a deck for a trick or offer to use one of their own if they have it. All examinable decks (most of them) are in the main compartment of my bag, those that are not are in a hidden compartment inside the main part so I don't have to worry about people with wandering hands and eyes.
With that, I have a sharpie and a handful of decks prepped for tricks. (ie Invisible deck, gaff decks, and many other tricks ready like angle-Zero and the like.
Oh, and an Advocate in your favorite deck of cards, ready at ALL times. Impromptu miracles will abound.
I say lots of things because that is what I carry for gigs. In reality, it is up to you and your style. I also keep things ready for Rich Ferguson's Tagged at all times. I combine d+M's angle-Zero, Burn, and Rich's Tagged for one of the greatest reactions I EVER get. I don't carry an invisible deck often anymore because I have the Advocate, which gives me the ability to do the ID without a super gimmicked deck. Find what tricks you like, do well, and can get great reactions from, and build your routine, complete with alternates and outs, then find out what you need to carry. I have several routines ready, one which uses only a single deck and one that uses one deck and just supplies I can hide in my pockets.
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