Section 33. The director may make such arrangements for any person, including a bank, to perform such functions, activities or services in connection with the operation of the lottery as he may deem advisable pursuant to the rules and regulations of the commission, for the deposit, handling and disbursement of lottery funds, tickets and materials, and may permit agents to deduct from the proceeds of sales of lottery tickets the agreed amount of reimbursement and compensation for services rendered. For purposes of this section the term ''bank'' shall include all banks, banking associations, savings banks, co-operative banks, credit unions, trust companies and any other type or form of banking institution organized under the authority of the commonwealth or of the United States whose principle place of business is within the commonwealth. Arrangements, and any negotiations precedent to their being contracted or made under this section, shall be open records, and should be made after such competitive negotiations as the commission finds are practical. The director shall cause all lottery funds, from whatever source derived, to be deposited in an interest bearing account until disbursed.