Specific guidelines exist.
Do not use the petty cash or impress method to circumvent using a requisition, because it will get kicked back. A pink UH Requisition form may be used as well. DO NOT make a purchase and expect to be reimbursed as was done in the past. Use a pink UH Requisition form. The bid can be awarded to a bidder with the best combination of price, features, delivery times, not simply the lowest price, but the case has to be made so there is no doubt what is the better overall deal.