I've been using egg layer crumbles chicken feed for about three months now for two cats and I swear by it, I pay $10 for 50 lbs at Tractor Supply Company, it clumps well and doesn't track too badly when used with the Booda Dome Clean Step litter box. It's not too dusty and doesn't have any nasty artificial perfumes, which you don't need as long as you're scooping daily.
I have been looking into the cost of litter for a week or two. Giving it some thought I have been able to trace the cost of litter to "how many pounds per cubic foot. Clay litter weighs a lot so more pounds go in the box to fill. In a case of corn cob or chicken feed the weight goes down per fill so for instance WBCL will seem to go a lot further than the clay. It's still just litter, It's just light. I will be soon contacting a manufacture of corn cob products in the midwest "corn country" to see what kind of pricing I can get per 50 pound bag buying in bulk... perhaps a pallet or two. I allready know the savings verses clay litter is substantial when thay are willing to ship 50 lb samples for peanuts. I'll post my findings and perhaps some cat owners in the Boston area would interested in taking advantage of a bulk buy. Or remote cat qwners could do it on their own. Just a thought.