It's been a while since there was a new 3 or 4 prize game, so this was an idea I had that's heavily inspired by Do The Math.
The contestant is shown three prizes. The prices of the lowest-priced and highest-priced prizes are revealed, but the price of the middle prize is a secret. The contestant is then given "the missing link" - a value that represents the difference from either the low and the middle prices, or the middle and the high prices. So it's a 50/50 decision of where to place "the missing link". Placing it correctly wins all three prizes.
For example: prize A is $1,000, prize B is $?, and prize C is $3,000. The "missing link" is revealed to be $500. The contestant decides if the link goes between A-B, meaning they think the middle prize is $500 more than A ($1,500) or if it goes between B-C, meaning they think the middle prize is $500 less than C ($2,500).
In addition: the value of the link doesn't always have to be the smaller amount either. The link in this "inverse" case could be $1500 instead. So if the middle prize is $1500, then a $1500 link would go between B-C (1000-1500-[+1500]-3000), whereas a $500 link would go between A-B (1000-[+500]-1500-3000).