This is a suffix that takes the on’yomi reading, which you’ve learned already!
You'll also see this pronounced ふだ, but that's when it's a standalone word or part of a compound, rather than a suffix. So if you answer with that reading, you'll be prompted to enter the suffix reading instead.
Could you give me change for a 10,000 yen bill?
Can you break this 2,000 yen bill to two 1,000 yen bills, please?
Apparently, there are many hundred-dollar bills hidden all over the Tofugu office.