I would not advocate the use of drugs for altered states, especially on a site filled with teenagers (and more, but mostly teenagers). If you want to look into opening your mind without drugs, look into altered states of consciousness and how to achieve them.
A bit about Karma.
You are speaking of the concept of what goes around comes around. It is not found in all cultures, and thus is not something universal and would be considered path specific.
"So if you cast a spell to increase your income, then maybe a few days/weeks later, it'll reverse and something bad might happen to you."
This is a concept found in the English book, The Monkey's Paw (note that it is fiction and categorized in the genre Speculate Horror). It is a story where a couple uses a monkey's paw to wish for 200 pounds and ends up getting it in the form of compensation for their son's death and then more horrible things happen.
Again, believing in something like this is up to each individual, though it is not something universal. Personally, I find this more to be paranoia, which can manifest itself because every action we do has (at least a very slight) effect on the world around us (thoughts as well, depending on your belief).