You won't save money. Most commercially-built computers cost less than those you assemble from scratch, because manufacturers get parts at low prices. First, get tools. A must-have is a wrist grounding strap.
Static electricity is the mortal enemy of microchips.
A big anti-static mat on which to do your work is a lovely thing to have. Let us start with a standard desktop PC, running Windows 98 and various productivity apps, like Corel WordPerfect Office, Quicken, CorelDraw, and Quake. Windows 98 is OK, more stable than its predecessors, and Plug N Play works well. You also want a scanner, printer, modem, speakers, 3D video for Quake, and a backup drive. Get an ATX midtower case to house all these pretty components.