In some cases yes. I use Chemi-Pure in my canister filters. I can buy the 10 oz. jars online for less than $6.00 each. Local stores sell it for $14.99 ea. I could buy 1 jar and pay for priority mail, and still save $3.00. When I buy several jars, the savings skyrockets.
lol i think they have all that stuff at PETSTORES, haven't been to one in a while though? but i think they exist, i went to one, one time, they had, they had.. prime.. fishfood, filters, media, EVERYTHING!
Definitely...I could spend probably $40 and be set for at least a year on fish foods and I have a 55, 75 and 125 all stocked to capacity (just saying I don't just have one fish lol)