PVC shower panels or plastic shower panels are by far the cheapest shower panels available; however, you won’t get value for money. Their construction doesn’t have a solid core and is therefore not overly durable. A few bumps or knocks will most likely result in a cracked surface, which water can then penetrate, meaning they need to be replaced. Also, you can’t use them on a bumpy or bevelled wall, meaning time and expense would need to go into preparing your substrate, potentially costing you more.
If you step it up a tier, laminate wall panels can look quite realistic whilst also having the added benefits of being easy to fit, with a variety of fitting options to suit any bathroom design.