you can source mississippi lime by going to their website and looking up dealers locally. I looked into this, got the spec sheets but never followed through. they have several different grades ranging from the agricultural stuff at 8 cents a pound or so all the way up to ultra pure lab grade stuff at I think, about $1.50 a pound if I remember correctly. I'm sure the prices vary greatly depending on location.
Bottom line is I have about 10 lbs of mrs. wages left - but when I'm done with that I'll be buying the lab grade (since mrs. wages runs about $2 a pound)