Newspaper pellets is the next best thing. Cell sorb plus comes in a 50 pound bag for 19$.
I don't believe they don't have puddles, the puddles may dry before you see them, but that doesnt mean they aren't walking through it wet and dry when you aren't watching. I think its inhumane to force any animal to live and walk in its urine and feces with no way to get off of it through a bedding material. The ammonia levels must be out of this world unless you clean their tub every single day.
Harlan Teklad sells many types of bedding material. Some are expensive, but dustless. There is even a product that looks like a nice thick paper towel. It's made out of cotton and the rats shred it up to make bedding, and it absorbs the urine and holds the feces as well.
Please don't keep them on nothing at all. That's just cruel.