even when you have to pay various expenditures, ....
「出費多端の折」は
even when you have to pay various expenditures, ....
のように表現できるかと思います。
to pay various expenditures で「様々な費用を支払う」
例：
Thank you for supporting us even when you have a lot of expenditures to pay.
「出費多端の折、ご支援いただきありがとうございます」
ご参考まで！
カナダ 
