Indoor cats - lessons learned about being thrifty/frugal with litter boxes (and failing)

What are your experiences trying to be thrifty/frugal with stuff for your cats?

We got this lovely girl at an animal shelter. She had been a feral cat, was around two years old, and was extremely shy and wary of humans. We also picked up a pre-owned litter box from the shelter, a basic one without enclosure or roof. Once she had settled in and felt comfortable with us, we got a kitten as a companion for her.

Litter boxes - Penny wise and pound foolish
We quickly realized that cheap, low litterboxes meant twice daily cleaning of the floor around it. We also learned that enclosed litter boxes are better, but some cats don't like them with flaps and will sometimes prefer to do their deeds outside the box. We went through five different models of litter boxes before settling for the top-entry ModKat (thrifted for half price at the cat shelter), and then we also upcycled a toy chest into an enclosed cat litter box. So all in all, we tried to save money on cheap litter boxes, but the one that was by far the easiest to clean and got the least amount of litter outside of it was the ModKat and the upcycled toy chest ranked second.

For the ModKat we first used liners (pricey!) that we bought from pet stores. But we soon discovered there was no point in having the liners, one of the cats just pulled them down and did their deeds between the liner and the wall. Instead it's just easier to just clean out the whole box regularily.

In summary: We wasted way too much money on finding good litter boxes.

Litter - The cheaper options tend to cost more money or labour in the long run

• Shredded paper cat litter, and shredded paper litter pellets, are very economical, but the whole house eventually reeks of ammonia and wet newspapers unless you change them out very frequently. So while the packs are cheap, you use more and the bags tend to take up space. Plus, the soggy paper sticks to their paws and tends to get around the house.
• Clumping clay litter is a bit more expensive, but the cheaper varieties are fairly dusty. We tried all kinds of varieties.
• Wood pellets (with special litter boxes), was about as cheap as the paper litter. It required once-or-twice-daily sifting, and twice weekly emptying. It did cover up the cat urine smell better than the paper, but as our cats didn't like stepping on them when it was freshly changed, they did their nr 2 outside the box. Also, there seemed to fly wood chips all over the room when we sifted. I used the wood pellets for our gardens instead.
• Crystal litter is more expensive, but it absorbs the urine smell very well and lasts for quite a long time with daily emptying. Alas, our cats didn't like the normal crystal litter (it seemed to hurt their paws or butts), so they did their deeds outside the box. So while I thought I had made a bargain when I bought 30 kg of crystal litter from an online pet store, I ended up having to give the majority away as it wasn't feasible for us at all.
• Clumping crystal litter was even more expensive, but the crystals were smaller and the cats tolerated it. But I noticed that it eventually formed a lot of dust, and both mine and the cats noses were runny whenever we went anywhere near the space where the litter boxes were. Plus, if they managed to track any crystals outside of the box, they hurt to step on for us.

In summary: We failed being frugal or thrifty, and spent too much on different brands of litter to find out which one was accepted by the cats. The litter we're using now is one of the more expensive clumping clay varieties, EverClean. But it lasts for longer, is less dusty, is well accepted by the cats (less boo boo's), there is much less cleaning needed and one month's supply takes up fairly little space compared to most of the other options.