Six reasons why Naruto Uzumaki will never steal money, no matter how badly he needs it:
Reason number one: You can't take it with you.
Naruto fully expects to die one day, not that he really wants to. Unlike other children his age, he is very familiar with the threat of death and how closely he comes to it at times—not everyone will be willing to stay their hand just because he's a child in need, and he won't be young forever, so unlike the other children he sees walking the streets of Konoha, even the ones wearing the Leaf insignia, he is well aware that he could die at any time from any number of things.
No amount of money in the world has ever prevented anyone from dying, though it can help, if the right person is involved, to prolong life for awhile and in varying degrees of comfort. Whether old or young, weak or hale, when it was your time to die, you died. Naruto, naturally, intended to be dragged kicking and screaming into the afterlife and make life, or rather unlife, hell for those who weren't already there; he knew, though, that it would be with empty hands, because money was a physical thing and spirits were not.
Reason number two: It can't buy you friends.
Now it isn't to say that Naruto has very many friends, if any at all; at best all he can claim are partners in crime or people who are willing to let him hide out in exchange for a cut of the take. Jewelry does sometimes enter into the boy's possession, but only to be pawned off or traded away for something more useful. It's not money so it doesn't count in his eyes. He has seen how the destitute flock to the wealthy and he hates it, because they're just in it for the money instead of any real gain of status or employment. Oh, sure, a rare handful out of the endless mobs of beggars that fill every city no matter how prosperous the nation are genuinely in it for entirely altruistic reasons, but most of them are just after the money out of some mistaken belief that it will make their lives better.
Naruto, for his part, is smarter than that. He knows that it's entirely possible to have a fruitful life without a single coin to call your own, to have a circle of friends a mile wide and a large, loving family, just as he knows that you could be richer than the gods and be bitterly alone every night. Granted, it cannot be said that Naruto has very many friends; he does, however, have family among his fellow thieves, even if they don't see each other as such, and those friends that he does possess have in him a more loyal companion than one could ask for. He watches their back and they his and the world continues to turn.
Reason number three: It can't buy you happiness.
Sure, money can be used to buy things that make you happy, but happiness in and of itself is not now nor will ever be for sale. That's just the way things are. He can count on the fingers of one hand the number of times that he's been able to use money to buy happiness and that number is so low that it's easier to make a fist and hit someone with it. There are many ways to gain happiness that don't involve money and one of them factors into the fourth reason; he has possessions, of course, everyone does save for those who take vows of poverty before entering religious service, but that's a different story entirely.
Not once in his life has owning anything ever made him happy. It's what he does with what he owns that brings Naruto happiness. Things gotten through methods both fair and foul are just things to him, the toys on his shelf get played with but they're just objects. A set of lock picks 'borrowed' from some hapless ninja, now those please him immensely, a good book as well; Naruto's happiness, however, does not come from having things. There is an old saying which states that it is better to give than to receive and Naruto employs it in his life on a regular basis. Seeing the orphans smile when he brings them something to distract them from the endless dreary and hopeless days waiting for adoption or emancipation makes him happy. So long as they smile and don't despair, then he will as well.
Reason number four: Money can't buy love.
Granted Naruto is still a little young to properly understand love, having never experienced it for himself, but he knows what it is and he knows people feel it. There are, of course, those that live for the love of money; cash, gold, jewels and other such wealth cannot love one back, however, and it ties in to the second reason quite nicely. An elderly berk with a drinking problem who constantly ranted about fairies once gave him very sound advice concerning the transition from friend to lover. It takes a friend to stand by your side when the shit hits the fan but only when someone truly loves you will they take a knife in your stead. For his part, Naruto hopes nobody ever has to get stabbed instead of him, given that he heals rather quickly; all the same he wishes to someday meet a person who he can have that sort of relationship with, though with any luck there won't be any bloodletting involved as proof of that love.
Though he might change his mind when he gets older, at the moment he doesn't care if it's a man or a woman that he falls in love with. Seeing a woman dumping all her fiancé's things out of their bedroom reminded him, too, that love is crazy, and people who love you for your money will just end up leaving you in the end to go be with someone who has more.
Reason number five: Money equals Danger.
That is, after all, why people who have it spend so much to protect themselves from people who don't. It is a fundamental truth that those who lack will always be jealous of those who don't, and even someone as large-hearted as Naruto is no exception. He knows Envy, and is close friends with it, especially when he sees the privileged offspring of old money walking down the streets as if they own the place, which unfortunately they likely do. These are the same people, he figures, who sleep with arms in close reach, because there is always someone who can get past the guards, past all the wards and traps, and breach one's inner sanctum to threaten life, limb and livelihood.
The wealthy are always in constant fear for it, in constant paranoia of being robbed or taken by the roadside and left for dead, or losing everything to some natural disaster or household accident. All the reasons tie together to varying degrees, Naruto thinks, though the fifth reason he's come up with he sees as standing at the very root of them all. And last but not least is his final reason.
Reason number six: Loyalty cannot be bought.
Like happiness, Naruto has never seen loyalty for sale anywhere in the confines of his world. He knows that most everyone works for money, because everything costs money to buy (and hence Naruto's life of crime because he never seems to have enough for the basics), but those who control the flow of cash would do well to remember that the people on their payroll can easily get the funds they need somewhere else. Sadly, most employers make the mistake of thinking that just because they are providing a necessity to their workers that they will remain with them if the money should suddenly dry up, and that's where it costs them in the end.
It's even worse when the workers are hired thugs or mercenaries; there are always stories circulating about some wealthy businessman or another that thinks that just because he's giving money away that his goons won't turn on him if he stops paying, especially if that employer is rude to his men, or cruel or any number of other things that people generally don't take kindly to happening to them. Those that live for the thrill of combat and follow a rich man around so they can slice up bandits and robbers know that they can always get their jollies somewhere else.
Like friends, loyalty has to be earned though it can be difficult. Naruto knows he has the loyalty of his companions because even though he only pays dues to the tax man, he's never crossed them and always treated them with respect, even if he speaks his mind more often than can be considered healthy.
Simply put, Naruto places no value on money and likely never will.