All purchases made and contracts executed by the city shall be pursuant to a requisition
from the head of the office, department or agency whose appropriation will be charged;
and no contract or order shall be binding upon the city unless the director of finance
certifies there remains to the credit of such office, department or agency, a sufficient
unencumbered appropriation to pay for the supplies, materials, equipment, or contractual
services for which the contract or order is to be issued. All such contracts and purchases
shall be made in accordance with all applicable competitive bidding requirements established
by state law, and either the city manager or the mayor may execute contracts compliant
with this section.
