the best i've used is repti bark great for borrowing
not so great and fun to clean up when cleaning the tank especially when you have a tank that is bigger than you can pick up. so i put newspaper down and tape it together, then i pour the repti bark in. then when its time to clean the terrarium i just roll the newspaper up with the reptil bark in it and its very simple.
to buy, the cheapest way is to order it online at that pet place .com
or get a free issue of the magazine at the website or call the number and get a free issue and then order it buy check
if you don't want to order buy credit card, really cheap that way
to see the defecation just look harder
and it sticks to the repti bark
and then you can just scoop it out