I have always gotten great liverock from
www.jlaquatics.com (figi premium) but this time of year you will get alot of die off because of shipping in the cold. ie. Longer curing time. Cost about $5.50 a pound for 1 box (65lb) when everything is said and done (shipping ect).
Locally I would recommend Blue world. They have some nice Liverock right now.