Hi, I'm not Theresa, but I do have the Fanny Lifter and I love it. You can use a reg step if you have extra risers. I used my reg step for a while with enough risers to bring it up to 12" for when the Fanny Lifter was used. The Fanny Lifter total height is 14" which I really like using. If you have access to a stool or any kind of step that goes to 14", you can use that instead. If you have "The Step", you'll have to turn it lengthwise to use it for Firm videos.
As far as the Fanny Lifter being worth the money, that will probably depend on each individual. I think mine is well worth the money. I use it almost everyday. I, of course, use it with every single Firm tape and I use it with any of Cathe's tapes where she uses the mini topper on her risers. When taken apart, the bottom section is 8" and the top section is 6".
Hope this helps. Kelley