Laura, I just got one of these at the beginning of the year and I absolutely love it!! The cost of material can't be more than 17 cents but they charge out the wazo for a simple piece of foam!! Still, I am so glad I have mine!
I **roll** my entire lower body on that thing. I start with the glutes, then move down to the hams, then shifting so all my weight is on one glute and one ham. I do the hips, quads, hip flexors, IT band, calves, hamstrings...you name it! If it is below the belt, I've rolled it! I've even done my shoulders before! That was tricky but they were sore from Muscle Max!!
Our local running specialty store has them. I bought mine at a Physical therapist place. Mine is shorter but 36 inches in diameter. I think it cost $15.
Oh, and it feels like a deep tissue massage! At first, everything is real sensitive and tender. After a few weeks, you can tell the knots are worked out.
Make sure you drink plenty of water when you use it...just like you would if you had a massage. You need to flush away the toxins.