The "cost" of a digital Shabar mantra isn't money anymore. It is discipline . Without a Guru standing over you, it is incredibly easy to download 50 PDFs, skim them for "enemy destruction" mantras, try one for three minutes, get bored, and declare the tradition fake.
Found in: Desi Nuskhe aur Mantra (1931)
Searching for "Shabar Mantra" on the Internet Archive can yield thousands of results. To find quality material, look for the following keywords and authors: shabar mantra internet archive