You're going to have to provide some more information, perhaps with some examples of valid entries and how you want them formatted.
The PDF is an insurance questionnaire, and the field in question asks "What is amount of your judgment/settlement"?
Currently, I have the field set as Currency with no decimal places (e.g. $ 4,123). In the event the answer to this question is "None" or "N/A", I'd like for the field to support both formats.
If you have the freedom to change the design/layout, I'd suggest adding a check box to indicate N/A. You can set up the check box to clear the amount field and make it read-only.
If that's not going to happen, what you want to do is possible, assuming that if the value of the field is a valid number then format it with that currency format, and nothing otherwise. This will require a custom format script. Post again if you really want to go with this approach.
I'd really like to pursue the second option as the current disign of my form is "optimal".
Your help is greatly appreciated....