There are supermarket peanut butters that are just peanuts. In New England, it's 'Teddie'. If you look at the ingredients, it's "peanuts, salt". The no salt version has a shorter list :-)

The health food stores around here all have peanut butter machines in their bulk foods departments. Might be true where you are as well.

One thing to know about this kind of peanut butter is that it separates: the oil floats to the top. I just mix it again but putting it in the fridge slows the separation way down.

Also: you've heard that peanuts and peanut butter contain the carcinogen aflatoxin. This is not part of the peanut plant but comes from a fungus that can grow on the peanut as they're aged post-harvest. The bad ones are easy to spot as they're black and moldy looking. Discard those - or trust your peanut butter company to have done so. There's a similar issue with corn meal as the same fungus can grow on feed corn. Nixtamalization (soaking / cooking in alkaline solution) is a traditional technique to deal with this (end result is called 'masa' flour) which long predates Columbus' "discovery" of the Americas.