obviously depends where and for who you are going to be flying and what their pay structures are on that contract/ contract client. normally no pay on your off month but a small retainer. say about 800/900 USD. figures below based on field allowances(s&t/perdiem) earned tax free daily and paid monthly back in SA for instance.
200/1900 co pilot about 3000 to 4500 USD per month.
captain about 4500 to 6000 USD per month.
hope this helps.