Except as otherwise prescribed by law and subject to limitations prescribed by the secretary of administration, state agencies may deposit in an employee use fund the following revenues:
(a) Gifts from employees and former employees of the state agency;
(b) profits from vending machines, coffee funds and similar functions;
(c) profits from garage sales and similar employee fund raising activities which have been approved by the head of the state agency; and
(d) interest earnings arising from employee use funds deposited in a financial institution.