A company called bathfitters installs liners that are acrylic. They make a decent product (it's about a 1/4" in thickness) depending if you get the matching surround to go with the tub, your looking at around $2,500.00. If you had your old tub ripped out and a new one installed, the price may or may not be lower. Another less costly option is a 3 or 5 piece tub surround. Swan makes a decent one for aroung $350.00. It's not those cheap flimsy plastic panels. Go to a plumbing supply retailer who has a showroom. You can get a better idea of what they have on display, see what you like in your price range and budget.