Some bathroom layouts don't require an enclosure at all. A consistent floor material makes this bathroom seem expansive. The open shower with just the tiled wall separating it from the vanity gives the bathroom a nice feeling of unity. Worried about keeping the heat in? Add a heated shower floor or a heat lamp in the ceiling (or both).
These are the most common waterproof bathroom walls. You can buy bathroom walls to go around your tub or shower that are made with acrylic. These walls come in a wide range of prices, shapes, and styles, but are usually white or off-white.
For super cheap, yet incredibly durable shower walls, nothing beats ordinary galvanized steel roofing. It is simple to install, vertically or horizontally, with ordinary screws and rubber washers to prevent leaking around fasteners.
Tiles can meet all of the criteria for good shower material, with many being water resistant or waterproof. They also come in a variety of colors and styles, and are easy to clean. The grout between tiles is less simple to clean, but many bathroom cleaning products make the work simpler.