Just be certain you are ready to tweak. I got one of the "Discount Tommy" Corona-style mills, and the quality control on those is non-existant. I spent probably 8 hours total trying to get the plates relatively parallel. I'm finally good enough on it.
Some work almost as is, some (like mine) require alot of filing, trips to the hardware store, drilling, tweaking, etc. The point is that, compared to a Barley Crusher, you are trading time for money. Barley works out of the box, the other requires an amount of time to get it going that can't be predicted.
BTW, if you do decide on a Corona mill, use google to look for "corn mill". Others have used one called the Grizzly mill, which costs about the same as the ebay (Discount Tommy one), but looks to me like a little better casting. I think Amazon has one or more sellers of these things as well. Garage sales are another place to look.
And I would forget about the 1/4 turn rule. You may wind up hitting the plates together if 1/4 turn goes in too far on the one you buy. One person broke his using a drill, assumedly because the plates locked up while spinning.
There are no less than 6 different mfg. of these things in China, so the castings will vary alot in quality, and you take your chances. I got mine working great now, motorized it cruises through grain and doesn't fly it all over as I assembled into a bucket with a protected lid. Just be aware it isn't plug and play...
Rich