@burcidi-- I agree with you. The best foot bath depends on what you need and it's best made at home.
When I had tendonitis, my feet and ankles were in pain all the time. Even the topical pain-relieving creams were not working. I went to a shop that had organic essential oils and asked the person there if they had something that I could use in a foot bath and which would relive pain. I was recommended rosemary oil and I bought a small bottle of it for about $15. But that bottle lasted me a whole year because I only need a drop of it each time.
It worked really well too. I would soak my feet in hot water with rosemary oil for half an hour before I went to bed. It was the only way I could fall asleep.