I am not knowledgeable with this kit, but I will try to help. The first question is what do you get in the kit?
Does it include the 8020.net components?
Does it include the angle iron for the guideways?
Does it include the bearings for the guideways?
Does it include the ballscrews?
Does it include the thrust and other bearings for ballscrews?
Does it include the frame materials?
Does it include motor couplers?
As a comparison the kit that I know more about is as follows.
I don't really think Joes hybrid would be much different in price once everything is purchased. The MDF may be cheaper, but if it gets wet it needs replaced.
www.cncrouterparts.com and www.finelineautomation.com
$1300 for the complete kit (everything but electronics)
$52.50 for each stepper motor, 380oz.
$52.50 for power supply
$15.95 for each cable
$290 for gecko 540 4-axis stepper driver
$1847.85 Grand total for everything
If low cost is your main goal then a smaller machine is the answer.
www.modularcnc.com is the best bang for the buck in small and low cost machines.