I mixed this very thing up last year. I think I found the recipe on some Ohio deer hunting forum - not sure. I put out the 200lbs in 3 different spots (so about 65+/- lbs per site). In one of the spots they hit it quite a bit for my low deer density area. The other two were pretty much not used at all or very little...but that could've just been poor choice of location. And, yeah, you can't get all that for $23 either.
I tried it because the trophy rock just doesn't seem to be a big seller to my deer. I should probably try the rock again though. I used to believe the media hype that all these minerals was somehow helping antler growth, etc, etc but after reading some of BSK's and other biologist-type posts I'm convinced that is not the case and all this "stuff" is kinda-sorta strictly an attractant and not much else. It makes sense to me that if some company could prove and claim that product "x" would grow bigger antlers then every Tom, Dick, and Harry would be using whatever "it" is to aid antler growth...and that ain't happening "yet"