What's the best substrate?

[Bogertophis]

Oh of course! No matter what substrate I'm going to change it out every month and spot clean weekly.
When I said "Last a while" I meant something I could buy in bulk? Just something that comes with a lot of substrate.

If you check various sources for similar products, you can probably find "bulk" sizes, & you can compare costs that way too, assuming you enjoy math. Generally speaking, bulk sizes do save you money, & I tend to shop that way too.