[SomewhatLikely]

Where I thought this might be going from the first paragraph:

Negative numbers are sometimes represented with parentheses: (234.58)

Tables sometimes tell you in the description that all numbers in are in 1000's or millions.

The dollar sign is used by many currencies, including in Australia and Canada.

I'd probably look around for some other gotchas. Here's one page on prices in general: https://gist.github.com/rgs/6509585 but interestingly doesn't quite cover the OP's problem or the ones I brought up, though the use cases are slightly different.

[oneeyedpigeon]

I was certain that it was going to be a range of numbers that didn't use an endash.