Help Picking Out a New Computer

I’m looking for a new desktop, and I tried customizing one on Dell’s website… but the price is way too high. Can someone tell me what they think a good price for the following specs is and where I could buy the parts (to build it myself).

Processor: Pentium 4 at 2.4 GHZ
RAM: 1 GB (kind doesn’t matter)
Hard Drive: 40-80 GB 7200 RPM
Operating System: None Needed
Floppy: 3.5 inch Floppy Drive
CD Drive 1: DVD-Rom Drive
CD Drive 2: CD Burner
Input Devices: Keyboard and Optical Mouse
Video Card: 64 MB Card Either nVidia or ATI
Sound Card: Lower End Non-Integrated
Networking: 10/100 Ethernet Card
Monitor: 19 inch CRT w/ a maximum resolution of at least 1600x1200

I have no idea where to start looking for this stuff or seeing if they are compatible, but I think that the Dell Estimate of 1,247 USD is way too expensive. Am I right? Or is that a good price?

Thank you so much for the help.