UCLA PO's
cdw To purchase with a PO, get a quote with shipping from the vendor, and email that to a purchasing officer (Mary Metz as of 2013). Email the purchasing officer a copy of the packing slip when the item arrives. If it's electronic delivery, email the confirmation. Following are in order of preference:
B & H Photo and Video offers great prices on electronic and some computer gear. They also have knowledgeable staff regarding professional audio and video.
CDW-G is a preferred vendor for basic computer parts (memory, hard drives) and as of 2013 has reasonably competitive prices. Get and education/government account to get the discounts (or use Paul's account).
Dell offers excellent prices for UCLA purchases. You will need to log on to a Dell premier account (ask Paul) to get prices and quotes. This is different to the education accounts. The IT help desk can also get a quote. Note that KST will fulfill the Dell orders, which is why some Dell orders will have emails come from KST.
The UCLA Computer Store can receive same-day PO's which means you can pick up items quickly. They have laptops and software, and a modest selection of computer equipment.
Vendors that don't take PO's
If less than $500, buy with a credit card, then put in the receipt, credit card transaction record from your account, and packing slip if shipped. Alternatively, you can cut a check and send that to the company, a cumbersome process. Finally, if someone has a P-card, they can use that. But be warned, you need to submit the receipt and packing slip (or other confirmation of receipt) within a very short time frame (3 days?), and these cards are prone to leading to all sorts of problems.
newegg usually has the latest products at excellent prices, but since 2012-2013 has been cluttered with lots of non-computing, consumer items. Good return policies.