All good stuff.
Here's a really neat trick.
Clap your hands, regularly, with a steady beat. After about 8 claps, pause for a few seconds, then resume.
Notice that very likely, if you are attempt to the claps and the silence in between, you will have very few if any thoughts in the pause between clapping.
Gradually extend the pause until it's as long as 8 seconds. Voila - 8 seconds not just of slow thoughts, but NO thoughts.
Mantra can be used the same way. You don't need a special one - just "blah"
blah blah blah blah (space/silence....)
blah blah blah blah (space/silence....)
blah blah blah blah (space/silence....)
keep lengthening the pause.
By the way, I just saved you hundreds of dollars, This is basically the transcendental meditation technique. You may need a teacher because the core secret of TM is effortlessness. If you make ANY effort to "try" to focus or "try" to quiet the mind that's not the point.
As it says in the Bhagavad Gita, chapter 6, the mind is quieted by withdrawing to a windless place.
This is symbolic of a 'place of inner silence THAT IS ALREADY ALWAYS PRESENT." you don't try to meditate; you just learn to recognize that Silence that is always "here" "behind" even the busiest thoughts.'
www.RememberToBe.Life