Stop poop bags from smelling for about $15. No I'm not kidding!!!

[Rajendora1]

Re square buckets?  The big square cat litter buckets.  Some of them come with pretty good lids.  You could use up the litter in the process.  Pet co has one you buy and then refill at a large litter sand box thing that might be sturdy enough.

 

[Kaylee]

Cost Update:
Just found a DollarTree (yippee!) in the closest town with laundry/etc, so bought a couple more of their 4 gallon bag bundles.
The count has dropped to 40.
That's still cheap, but I wanted to warn folks.