never have seen mazuri at either petco or petsmart. I know some forum members sell it, I purchase 25# bag at
a feed store that handles purina mills products it runs me around one dollar a pound by buying a 25# bag.
also try e-bay
I buy the 25 pound bags at a farm and feed store in Southern Maryland and the cost is a little over a dollar a pound, they don't keep it in stock but will get it for me when I need another bag.
Petco and Petsmart dont carry it. Your local stock shop should have it and some mom and pop pet shops may have it as well. What state are you from? Chances are that someone on this forum is pretty close to you so they will be able to tell you specifically where to get it from.
Theres a boatload of people from SoCal here so they will be able to tell you what stores to go to and hopefully there is one within reasonable distance of you.
I sent it priority mail this morning. I threw some spineless cactus in there as well. You might want to plant a pad and feed the rest. It grows quickly. I plant it it moist, sandy soil and it does well. The cactus does have a few small spines on it so be careful.