Why make plans of your own when you can steal someone else's and claim the credit?
This applies equally well for the GM and the villain's plans. Just borrow some evil plot from a book or movie, file off the serial numbers, and present it as something cool that your bad guy is up to.
Even better is when you take a plan from the PCs and twist it ever so slightly into something the evil villain is attempting to do. Think of the look on your players' faces when they realise that what the villain is trying to do to the rightful Queen is exactly what they did to the Goblin King.
Commentary by memnarch (who has not seen the movie)
Buy their freedom? I'd thought they were street urchin stablehands, not street urchin stablehand slaves. They do have a better plan though. Having or knowing where to get the resources to do a plan makes it so much better. Any bets that the only thing that the kids haven't been able to do is collect the money? That'd be a good way to have both groups help each other. Assuming Finn and/or Rose can claim the winnings without getting arrested again.
Ooo! Or maybe Finn or Rose proposes taking the fathier bets from the kids in exchange for a ride off-planet. Sure, there could be complications still, like the rigged fathier bets being discovered and nullified, and a heist still needs to happen. Or that the ship Finn and Rose came here in was impounded because they escaped from jail so a different ship needs to be stolen. Or the First Order shows up here for some bizarre "time for more fighting" movie director reason and attacks the casino. But that all sounds like much more fun than simply playing the odds anyway, so here's to hoping some of that happens.
Transcript
Rose: You have money? How much?
Arashell Sar: 6000 credits.
Finn: That seems like a lot.
Oniho Zaya: It’s a casino world. Fat-cat patrons don’t just drop small change, you know.
Arashell Sar: But it’s still not enough to buy our freedom.
Temeri Blagg: Tha’s why we ’ave a right plan, we do!
Rose: Oh, I love a good plan!
Temeri Blagg: We’ve bet all our sausage on the fathier races.
Arashell Sar: Wait. You did??
Oniho Zaya: And... we rigged the races! It’s easy for streetwise urchins like us with access to the animals.
Rose: That was my plan!
Temeri Blagg: Only we made it be’er, guv’na.
Rose: How so?
Oniho Zaya: With (a) a means to rig the races and (b) actually having money to bet.