HP, Pre-World Cup

Ludo Bagman looked slightly disappointed, but recovered himself. “Very well, very well . . . any other takers?”
“They’re a bit young to be gambling,” said Mr. Weasley. “Molly wouldn’t like —”
“We’ll bet thirty-seven Galleons, fifteen Sickles, three Knuts,” said Fred as he and George quickly pooled all their money, “that Ireland wins — but Viktor Krum gets the Snitch. Oh and we’ll throw in a fake wand.”
“You don’t want to go showing Mr. Bagman rubbish like that —” Percy hissed, but Bagman didn’t seem to think the wand was rubbish at all; on the contrary, his boyish face shone with excitement as he took it from Fred, and when the wand gave a loud squawk and turned into a rubber chicken, Bagman roared with laughter. “Excellent! I haven’t seen one that convincing in years! I’d pay five Galleons for that!” Percy froze in an attitude of stunned disapproval. “Boys,” said Mr. Weasley under his breath, “I don’t want you betting. . . . That’s all your savings. . . . Your mother —”
“Don’t be a spoilsport, Arthur!” boomed Ludo Bagman, rattling his pockets excitedly. “They’re old enough to know what they want! You reckon Ireland will win but Krum’ll get the Snitch? Not a chance, boys, not a chance. . . . I’ll give you excellent odds on that one. . . . We’ll add five Galleons for the funny wand, then, shall we. . . .” Mr. Weasley looked on helplessly as Ludo Bagman whipped out a notebook and quill and began jotting down the twins’ names. Rowling, J.K. Harry Potter and the Goblet of Fire (p. 35). Pottermore Publishing. Kindle Edition.

Harry narrowed his eyes, having seen the type before, and spoke up before Bagman… Oh how alliterative… could write anything down. “At what odds? And remember, the-boy-who-lived backs them and will absolutely ruin you if you bag them. Bagman.” Causing Ludo’s quill to stab through his notebook and his features to begin to sweat.
“I see. Boys I’ll give you 50-1 odds on your bet which means, rounding up 2000 galleons, if you win. AND I’ll have Hermione write out the contract for it right now for it. Can you match it MR. Bagman? Or will you match my bet with the five galleons for the wand?”

The five-galleon bet was made instead by the sweating Bagman who ran away as soon as he could.