I'm not mystical by any means, but I truly believe when you do bad, you get it back. Anyway don't take me wrong, I am not trying to judge you, I just don't like seeing vunerable people being taken advantage of.
Both this topic and especially this post made my laugh. This type of thinking only holds one back. "Bad" is relative, the only distinction that matters between those that succeed and those that fail is intelligence. The buyer in this instance lacks intelligence and so they solidify their position as a epsilon cog who is bound to a mediocre existence for the rest of their life. Nothing wrong with being an epsilon, but to be an alpha one must not act in a utilitarian fashion.
As far as this method is concerned, selling religious healing also works well. I no longer do it since ebay banned me for other reasons, but up to the point that I got banned i was averaging a couple sales a day at 7$ each. Just offer it for illness and internal injuries. Not for broken bones and missing limbs. If you market it for specific religions it works well since the individual does not like to see his/her religion proven wrong. Placebo is a strong force as OP mentioned.