The price is the destruction of millions of trees in North America, including rare old-growth forests. And it's not just trees...
"Turning a tree to paper requires more water than turning paper back into fiber, and many brands that use tree pulp use polluting chlorine-based bleach for greater whiteness. In addition, tissue made from recycled paper produces less waste tonnage - almost equaling its weight - that would otherwise go to a landfill."
Yeah, but what choice do we have? We want toilet paper. Don't we need to cut down trees to get the paper? Nope. There's post-consumer recycled tissue products.
You can get guides from Greenpeace and the NRDC to the environmental soundness of tissue brands.