How do I work with currency fields in Salesforce

Campaign Monitor does not support currency fields it only has a number data type.  If you want to pass across a currency the best option is to create a formula text field in Salesforce.

This way you can include in your formula a currency symbol.  In addition, should the amount end on a zero for example $100.00 this will ensure the whole number goes across. Both Salesforce and Campaign Monitor can truncate the number field causing the last zero behind the decimal point to be removed.

Ensure that you map the Salesforce formula text field to a Campaign Monitor text field.