Yes I have. I love the product. It is not the same as the "carbon paper" that is used in sewing with the toothed roller. The paper is much finer, about the weight of tracing paper. The transfer substance works very well and is easy to see but it also rubs off easily like chaulk so unless you are putting the quilt on a rack, I would consider it a mark as you go product. The marks do not hold up to any kind of rubbing and come off very easily (too easily in some cases). It is reusable and I have transferred a lot of designs with one sheet but some colors seem to last longer than others, like the white I have been able to reuse a lot. Additionally the other colors I have not had any problems with them washing out.
That said, I too find it very spendy and am seeking out less expensive alternatives. Many here have mentioned Saral paper which is used for folk art/tole painting. I am familiar with this product from my tole painting days but have not used it to mark fabric, even though the manuf. says it is fine for fab. I plan on getting the white and graphite only of Saral.