what you do is ... you talk to the guy, and take ALL of his LR ... and take it all for $2.00 - $2.50 /lbs ... then you take what you need, and the rest you take to the fish store ... most stores will buy the stuff from you ... i know rich @ board room has always bought my excess rock .. .eventhough last time i was there .. few weeks ago his LR bin was filled to the top, and then some.
btu the store will probably give you ~$4-$5 /lbs. ... that makes up for your hassle, and then some extra play money.