Any advice with emptying bedside commode without it going all over floor?

I found bedside commode liners on amazon that have a small strip at the bottom that helps to solidify the liquid waste. However, my mom is on a diuretic and I also add a good grade of kitty litter to the bag.The bag has a tie on it so all I have to do is gather up the tie and lift it out of the container, I don't have to wash anything out and the kitty litter knocks out any odor and keeps the liquid wast solidified.The cost of the liners is about $1.00 a day, well worth it.

Actually one of the easiest solutions is to get a cheap flushable kitty litter and a scoop. Buy one that is scented if it that isn't a problem or add baking soda. You can also check into getting a deeper insert for the commode.
Also as Captain said older toilets waste a lot of water. You can sometimes get away with filling whatever sized bottle you can fit in the tank to take reduce the amount of water needed to fill it. Keep a close eye on it if you choose to do so till you know it works.

if your water bill is high its possibly because the float assemblies for toilets are non functional chinese trash nowdays and the ball stoppers dont hold water back even when new. if a toilet seeps even a little stream of water into the bowl it can drive a water bill out of sight. i gave up and just put a water shutoff on my toilet. i turn it on to fill the tank / flush, off when im done.

In hospitals, I know, they sometimes use cardboard liners for commodes, which are then disposed of complete in an incinerator. I don't know if there's anything similar available for domestic use (one that doesn't need an incinerator, for a start) - what about contacting your local health care organisations and asking if they can recommend something manageable by people with a disability?