When I set my 32" x 32" basement shower stall, I had a sack of Armstrong leveling compound that I had no use for, so I used that. It mixes up very soupy and runny, so I did have some oozing out to deal with, but a few narrow strips of an old towel make a temporary caulk that kept most of the ooze contained, and after the stuff set up, the ooze was easy to chip off. Using this stuff allowed me to set the stall in place, level it perfectly, and attach the drain before I poured. As I was working alone, I had visions of having mortar setting up before I could get the stall in place and leveled, so this seemed to be a good use for material otherwise going to waste. I really worked well! That stall is solid as a rock. The bag of stuff was fairly large, but I don't remember the weight. I think it was quite inexpensive as well. I used a mixer auger on my 3/8" drill driver to mix the goop in a 5 gallon bucket. I think it took a couple of batches. A larger stall would require more that a single bag, but it's cheap and easy to use.