The mill you've linked above is >$1000 and that's without CNC motors or drivers. The DRO is great for manual milling but at the end of the day it won't get you any farther than the Dremel in a drill press for PCB work.
You can easily spend $300-$500 on CNC motors, driver, and PSU. If you want a whole system for under $800 you will have to build it yourself. If you have access to shop equipment there is a set of plans you can buy for a machine called the "Brute" (google for "Brute CNC") which will do PCB milling and drilling pretty well. Having built one, I like it, but milled PCBs are not half as nice to work with as fabbed ones. No silkscreen, no solder mask, and no through-plating. For $800 you can order a lot of PCBs online from places like Batch PCB. Building your own CNC can be fun but if you just need a dozen custom PCBs then pay someone else to make them.