Okay, this cost me $100 per bag over $15 stuff from Lowe's. Was it worth it? for my application on a heated floor I had no choice, but, I'm glad I discovered this product, I really don't think I'll ever use anything else. Ease of application, it is so smooth and easy to work with, that in itself really does offset part of the cost. You really need to clean up good right after because this stuff, if it dries on your skin its like getting gorilla glue off, seriously. I was glad I discovered that anyway, I used it on the walls too and theres nothing gettin that off. I'm just glad to know its stuck, and I mean bullet proof, it adds to the overall structure in a way a normal tile job wouldn't. Just because of the expense it may not be for everyone but anytime you can afford it on a project, this is the only thing to use. On this one for me, I had already lost 40K on a bathroom remodel on my Dad's house and a couple hundred bucks extra for such an essential structurally important part, I wouldn't consider the 15 dollar stuff on this one. On this one I'm putting grab bars in it for an elderly person and those walls needed to be pretty sturdy. I don't do this for a living but still glad I discovered it I will always use it where I can, there is no comparison to the cheap stuff, For me it seems to be worth it.