Just got myself 5 boxes. Pretty good price.
http://www.petsolutions.com/C/Aquarium-Salt-Mixes/I/Instant-Ocean-Aquarium-Salt.aspx
http://www.petsolutions.com/C/Aquarium-Salt-Mixes/I/Instant-Ocean-Aquarium-Salt.aspx
I'm extremely impressed with the shipping speed as well. I put my order yesterday afternoon and tracking shows that the salt will be delivered tomorrow.
Sea creatures in n.providence sells them cheaper than that if you dont mind the ride
Additional 15% off makes 200 gallon box of IO for $34.00 with free shipping. Just got myself 10boxes.