You will need at least the following parts to build a basic Linux server.

1. •Case - To hold all the other parts.
   

2. •Logic (Mother) Board - The interface between all the components.
   

3. •Fan - To keep things cool (in some cases, the fan is already provided).
   

4. •CD/DVD Drive - So you can install software.
   

5. •Hard Drive - To install your operating system onto.
   

6. •RAM - The local memory that the system uses when it is powered on.
   

7. •CPU (Microprocessor) - The heart of the systems that does all the thinking.
   

8. •Network Card (Optional) - To connect to your network. Most Logic (Mother) boards have a built-in network connector.
   

I picked up these parts at my local Fry’s Electronics store for under $500.