Upon presentation of a valid voucher application, the corporation shall issue from its insurance subsidy fund a voucher to the guardian or applicant aide, made out in behalf of the guardian and redeemable for the face amount by any approved provider. The corporation shall retain in the fund all moneys received from refundable tax credits of guardians. These moneys shall be used to extend additional vouchers. The corporation may solicit and receive donations of moneys for the fund. No corporation may require that vouchers be presented to a specific approved provider in order to be eligible to participate in the program.