The single most important investment you make in a dance studio is your floor. You can teach without barres and mirrors, but without an appropriate dance floor system you are in deep trouble. When it comes to cost, and that includes purchase, installation, and upkeep, your floor will occupy a good chunk of your time and money.
Your flooring system allows you and your students to perform and practice safely. Unfortunately, there is a lot of bad and dangerous information out there on the internet. Cutting corners and "saving" money is not in itself a bad thing. There are issues to be considered before you plunge into making a choice that in the end will cost you more and jeopardize your health and the health of your students. I have seen and read conversations about using shower or roof liners for flooring as a way of saving money. In a word, that would be a foolish and dangerous thing to do.
First, these products were designed to be vapor and water barriers sandwiched between other products. They were not designed for exposure to the air, let alone to be cleaned with detergents or to directly handle foot traffic. Exposed to the air, the plasticizer in these products evaporates rapidly, shrinking and aging them. They are not fire rated, which means you can be closed down for using these products as floors. Since they are not specified as flooring, whom do you go to if there is an issue with wear, defects, or how to install them? They come with no guarantee.
This is the kind of deal you need to avoid. It should also be noted that many dance floors have antibacterial and antifungal additives that help keep your floors hygienic. Needless to say, the liners lack these additives. If money is an issue, do you have enough to do your floor twice? If these were appropriate products ask yourself why did the Marley Corporation, which made roof and shower liners, develop a new product, Stageflor, the reversible dance floor, back in the 1970's? The answer is very simple. Liners are not a viable option for your studio.
On the maintenance front, there is also a lot of bad information being disseminated online. First are the no-no's. NEVER use: vinegar, bleach, coke, alcohol, oil, ammonia or household detergents on your floor. While they may have an initial positive result, the net effect is that they are either dissolving your floor or making it slippery. Use products recommended by the flooring manufacturer. In many cases if you use non-recommended products you could void the warrantee.
And finally, washing your floor with just water is basically a waste of time. Body oil from sweat and body lotion the dancers may have applied get on the floor. Water doe not dissolve oil, so when you start mopping the floor you are spreading the oil over the surface of the floor and not getting it up.
If your floor has a hazy, satin look to it, it is probably loaded with oil, which will attract dirt and contribute to making your floor slippery. Use a detergent/degreaser and water combination and the oils will dissolve and your floor will be really clean. These products are usually available from a hardware store or from the flooring manufacturer.