I use it along with composts and alfalfa to create a healthier microbial environment. There's an additional benefit, that it provides more organic material for decomposition and soil aggregates.
It goes for about 15 bucks a kg (2.2 lbs) which is not prohibitively expensive.

I also add minerals from the Dead Sea. It always looks weird when I bring back soil, but I really believe it makes a difference because of depletion issues where I live. It's pretty simple, just to go there and bring back some dirt. :)

Here is a link that might be useful: Dead Sea Tours