Match [any] dollar amount

I need to search inside the contents of PDF invoices. One piece of data I need to obtain is the dollar amount. I will then use this to rename the file (which I already know how to do).
The problem is that invoice amounts are always different and with a different number of digits. Therefore, I can't simply come up with a pattern for X number of digits.
What would be the best approach to achieve this?
Thanks in advance for any help.
The problem is that invoice amounts are always different and with a different number of digits. Therefore, I can't simply come up with a pattern for X number of digits.
What would be the best approach to achieve this?
Thanks in advance for any help.