What is the term for an amount of money a member has coming out of his regular pay?

The term for an amount of money that a member has coming out of their regular pay is referred to as an allotment. An allotment is a portion of a service member’s pay that is designated to be sent directly to another person or institution, such as a family member or a savings account. This system is commonly used by military personnel to efficiently manage their finances, ensuring that funds are allocated according to their needs or obligations.

In contrast, the other terms refer to different financial concepts. A commission typically refers to compensation based on sales performance or achievement rather than a set amount of pay. A deduction generally indicates an amount subtracted from gross pay, such as taxes or insurance. Salary is a broader term for the total compensation a member receives and does not specify how that pay is distributed. Thus, "allotment" is the most precise term for the concept defined in the question.