Poor Man's Mach3 Pendant
Now it's perfectly OK to use the keyboard and mouse to control and zero your X, Y and Z axis at the first of a job, but it's not always convenient. Most CNC setups I have seen have an easy to use hand-held controller called a pendant. Some DIY pendants use video game joysticks that don't look very professional, cost money if you don't have one laying around and take some extra effort to setup with lightly documented unsupported software packages. Buying a professional 3rd party pendant is definitely an option, there are some very nice options out there but I couldn't justify spending $100, $200 or even $500 for a premium pendant, not for my needs.
If your a fan of Mach3 you know how easy it is to define keyboard keystrokes to do CNC operations. But I thought we were getting away from using the keyboard? Well...sort of. There are loads of USB 10-key keypads that have a pretty nice physical size and are effectually small keyboards so programming them in Mach3 is the same. The one problem of using a keypad, or a keyboard for that matter, is that you have to memorize what keys do what functions, enter pre-made Mach3 keyboard stickers.
If you have function needs not shown, you can even make your own stickers or just use these as blanks to cover keys you don't have programmed.
By using the keyboard stickers on a 10-key keypad instead you now have a very functional CNC pendant for about $20. Add in a USB extension cord if you don't have a front USB port or just need the extra range.