Projects typically need stuff: servers, software, subject matter experts, pizza, etc. And to buy all this stuff, you need to go through procurement processes. That's just a fancy way of saying you need to follow some rules and procedures within your organization to get the things you need to complete your project.
In some organizations where I've consulted, the project managers can spend carte blanche up to $10,000 on any purchases they need. In other, less fun organizations, the project managers can't buy a soda pop without an accountant's permission.
So where are you? Do you get to buy, buy, buy, or is every purchase considered, weighed, and meditated on before someone reaches for the wallet? In either shop, there are some guidelines you should consider.
Really, there are.
Planning What To Buy
All purchases require some level of planning. The intensity of the planning is relevant to the purchase being made. You do this already, right? If you're about to install a new piece of hardware, you'll consider all the functions that the hardware should have, shop around a bit for prices, and then see how much your project or organization can spend (or is willing to spend).
Planning for procurement includes more than window shopping. Think way, way back to the start of any project that required procurement. Early in the project planning, it was easy to identify those things or services that you needed to buy for the project to succeed. As the project moved forward, "emergencies" popped up, requiring you to buy more stuff: cables, software, additional hardware, tools, training, spaghetti sauce, whatever. So how did you go about getting all this stuff? Did you go to management, hat in hand, and plead your case for your much-needed spaghetti sauce, or did you dip into a project contingency fund?
How you go about purchasing depends on the structure within your organization. It's difficult, if not impossible, to define a universal approach to procurement. Everybody, every organization, has a specific approach to procurement. The moral of the story? Follow the rules. Once you know the rules of how to procure, then you can play the game.