Yeah, holding torque means very little. It only speaks to static (non-moving) loads. Everything in CNC is dynamic; moving loads so what you need to look at is the weight you wish to move or the torque required to move it, and how quickly you wish that motion to be. This is the measure of the power required which can be estimated in Watts and then translated into what amperage and voltage your motors and drive must deliver.
This page: techref.massmind.org/techref/io/steppers.htm#Estimating Has some "rule" of thumb calcs that may help translate the weight and speed you are hoping for into drive wattage, and explains how to translate that into voltage and amperage which will then allow you to pick out a suitable power supply, driver, and motor.
The motor you are looking at is very small with only 12 Watts of drive power. It will spin at a maximum of 600 RPM in unipolar mode (less in bipolar) and could move a 6lb load at about 1000 IPM.
If cost is an issue, you might want to look for used motors or scavenge old office equipment for free motors. There is a list with some good sources at: