I bought the baby bjorn potty and it's very easy to clean and not expensive at all. Just lift out the bowl part, dump the contents in the toilet, rinse in the sink (but dump this water in the toilet so no poop germs touch the sink). Then once all the poop is rinsed out, I scrub it with a sponge in the bathroom used only for this purpose. I keep a bottle of dish soap in the bathroom. Squirt some in and scrub it out. It cleans up really easily. Nothing sticks to it as long as you dump it right away (and who wouldn't?).
As long as you use hot water, the dish soap will clean as well as harsh cleaning products without exposing your child's little bottom to dangerous chemicals like bleach.
There have been many studies that show that washing hands with soap and hot water is just as effective at killing germs as the antibacterial stuff. Using antibacterial soap and hand gels actually contributes to resistant strains of bacteria and more dangerous illnesses and when they are washed down the drain, they contaminate the ground water. Bleach also degrades plastic by the way, so it should not be used on something like this. Besides, it's your kid's germs. It's not like it's a public toilet.