Why didn't Qui-Gon Jinn use his Jedi mind tricks to exchange his Republic credits?

Question

In Star Wars Episode I, Qui-Gon Jinn tries to use his Jedi mind tricks to convince Watto that Republic credits will do fine as payment for the hyperdrive they need. Conveniently, mind tricks don't work on Watto because he is a Toydarian, so Qui-Gon has to hatch an elaborate plan with Anakin and his secret pod-racer to win the Boonta Eve Classic and gamble with Anakin's life to win the hyperdrive and Anakin's freedom.

Why didn't he just go to a money changer who wasn't Toydarian and use his mind tricks to exchange his credits for something that Watto would accept? Then he could have just straight up traded the pod-racer for Anakin, or bought him... and Shmi too for that matter, since Watto ends up selling her anyways.

Answer 1

Although it may sound like a cop-out, the answer is that it was because the Force didn't tell him to. Qui-Gon Jinn was drawn to the only junkyard in town that had a compatible hyperdrive. When faced with an apparent obstacle, he simply waits for the Force to present him with a solution. Presumably when you're a powerful Jedi these kinds of coincidences happen all the time.

The novelisation is a little more clear on his motives.

“All right,” Qui-Gon responded with a frown. “Another solution will present itself. I’ll check back.” He tucked the comlink beneath his poncho and signaled to the others. He was moving toward the street again when Jar Jar grabbed his arm. “Noah gain, sire,” the Gungan pleaded. “Da beings hereabouts crazy nuts. We goen be robbed and crunched!” “Not likely,” Qui-Gon replied with a sigh, freeing himself. “We have nothing of value. That’s our problem.” They started back down the street, Qui-Gon trying to think what to do next.

A few seconds later, after having learned that pod-racing is a big deal in these parts, they encounter the same small boy from the junkyard. He offers them both assistance and insight into a way in which they can parlay their one solid asset (the ship) into enough money to buy a hyperdrive.

This has the added benefit of saving them from having to wander around town announcing their presence to all and sundry, remembering of course that their enemies may be on the lookout for a Naboobian transport ship or they may encounter people who're just flat-out unfriendly to the Republic:

“The Republic doesn’t exist out here,” Shmi interrupted quickly, her voice hard. “We must survive on our own. ... And they need my help. They’re in trouble. The prize money would more than pay for the parts they need" ... “Do you know of anyone friendly to the Republic who might be able to help us?" Shmi stood silent and unmoving as she thought the matter through. She shook her head no.

Answer 2

Watto didn't want to part with Anakin so I don't imagine it would have mattered what Qui-Gon had; he could have brought anything to Watto and it's unlikely that he would have accepted. Watto was willing to gamble Anakin only because he had a weighted set of dice. When Qui-gon used his powers to make it land on blue, Watto was mad but had to accept it.

Qui-Gon had a specific mission; Shmi wasn't part of that. Her presence would have interfered with Anakin's ability to remove himself from attachment, which was vital to his training, so while he opened with his haggle for both, and his morality might have made him give a half-hearted bid at her and promise Anakin he would have a go, he wasn't going to jeopardize the possibility of Anakin, his main mission, to get her.

He never really wanted Shmi, and Watto was never going to part with both... you never open with what you really want in a negotiation; Anakin was the goal. In the aftermath of the race, Anakin did ask about his mother, and Qui-Gon DID say he would try; but even if he had wanted to go back for Shmi, it's likely that Watto, with this loss to an 'outlander', would be all the more stubborn and hardened to withhold Shmi just to spite him.

QUI-GON : I'll wager my new racing pod against...say...the boy and his mother.
WATTO : A Pod for slaves. I don't think so...well, perhaps. Just one...the mother, maybe...the boy isn't for sale.
QUI-GON : The boy is small, he can't be worth much.
WATTO shakes his head.
QUI-GON : (Cont'd) For the fastest Pod ever built?!
WATTO shakes his head again.
QUI-GON : (Cont'd) Both, or no bet.
WATTO : No Pod's worth two slaves...not by a long shot...one slave or nothing.
QUI-GON : The boy,then...
WATTO pulls out a small cube from his pocket.
WATTO : We'll let fate decide. Blue it's the boy, red his mother...
WATTO tosses the cube down. QUI-GON lifts his hand slightly; it turns blue. QUI-GON smiles. WATTO is angry.
WATTO : (Cont'd) You won the small toss, outlander, but you won't win the race, so...it makes little difference.

While his moral compass would allow him to flip the dice Watto rolled to get Anakin (which had been rigged anyway), he wouldn't use it for 'side' activities on side parties; those not directly in his path. He did use it on the drug dealer, but that is because the crime was immediately affecting him, in his line of work, and was in his way.

It is entirely possible even the money changers didn't accept Republic credits; 'The Republic doesn’t exist out here' seems rather final, and against the idea of them accepting Credits for local money. He was an outsider trying, for the most part, to be under the radar and so minimized his use of Jedi powers; there wasn't anyone friendly to the Republic there to back him up, and being caught mind-tricking a cashier to accept a credits trade could bring unwanted attention down on him.

In the event they might have accepted Republic credits, given their vow of poverty, I would postulate they were more as the way nuns and priests operate, given cards to be used in the line of duty, but not removed them from the system to be exchanged for currency, where they could not be tracked for usage.

Answer 3

I think the question is based on a false premise that it is easy to find someone who will exchange the credits for the required currency. However, this isn't the place where you simply go to some local currency exchange. No one really needs your credits in here. The question also assumes that you just have to find someone who isn't Toydarian. But as we know, the mind tricks require the victim to be weak-minded, it's not about the race.

Together this means that Qui-Gon needs to find someone who (a) has lots of money, and (b) is a fool enough to be susceptible to mind tricks. This is a rather rare combination already because a fool wouldn't know how to make money and not lose it fast when he does.

But even if we assume that there are such people, remember that Qui-Gon is trying to not attract too much attention. Running around with a large sum of money and trying to use mind tricks on people hoping that it will work is exactly the opposite of that.