Red Coral's prices can be very good. Sometimes they're the same as J&L's, but sometimes they're a little more. The prices on Red Coral's website are the same as in store. I'll opt to purchase from Red Coral (even if the item is a little more than J&L) if they have the item I'm looking for, as (IMO) there is some value in instant gratification.
I love Red Coral's dry rock. They've also got Salifert test kits. I know they had refractometers in stock the last time I was in there.