When you create a monetary custom field for a custom object, it's displayed without any commas or spacing making large numbers hard to read. In the attached screenshots, I have entered $500,000 and $50,000 and they have both appeared as a "5" with a string of zeroes making it hard to read the numbers. It would be good practice to adopt the formatting for the relevant currency and put a comma in the correct position to make the numbers easier to read and interpret.