I haven't actually taken TM as a training but have gone to a few group sessions. I found them to be very beneficial in terms of increasing mindfulness and clearing my mind. I also know that there are quite a few online training programs out there that may cost a little less than the face to face ones. Maybe that can be a less costly option tp consider.
I've researched different online videos and meditation apps, but supposedly TM is a very specific practice that must be learned through a certified teacher. There's even a ceremony that must take place when a student is given his or her mantra.