Apparently, the only place I can get Lieber's Unsalted Tops Whole Wheat Snackers is from Mercato.com. However, they have a $35 minimum order, and I don't need $35 worth of groceries right now, so I'll have to try them at some other time.
The Organic Stone Ground Wheat Crackers had 100mg of sodium per cracker, so I passed on that option and bought Carr's Whole Wheat Crackers, with about half as much salt (55mg per cracker), instead.
I was surprised by how much I liked this product, which is likely to become one of my go-to snacks. It was thicker and heartier than I was expecting, sort of like a cross between a graham cracker and a cookie. (At $4.49 I guess I'll be paying approximately 20ȼ per cracker.)