There are independent contractors who will only do your tile, maybe include your coping if you decide to do both. You can depend on them to supply tile samples; or you can go online and research what’s available. There are sooooo many choices, almost too many styles to choose from. Tiles come in one complete six by six inch tile, or in sheets of different sized tiles that complete a pattern. There are also porcelain, ceramic, or natural stone tiles. My advice is find a contractor and ask questions. A good one will listen to what you want, or are looking for, and help you find one that compliments your pool and surrounding area; also the climate you live in.
National chain pool stores will have equipment for sale, but they may not have service people on hand to do installation. You will find cheaper prices for the equipment you purchase, but without someone who knows how to install it you are stuck. Also, understand, some independent service contractors will not install equipment that was not purchased through them. Many contractors have brands they trust and know are reliable. Installing equipment they’re not familiar with, or don’t trust, makes them liable for return (usually unpaid) visits to fix what is not their fault.
A hometown pool store should have both equipment and installers. You will probably pay more for the equipment, but you will also have the confidence that both your equipment and installation will be under warranty.
If you want to change the surface of your pool, my first advice is DO NOT PAINT it. Even though painting is your cheapest fix, consider the old adage, “You get what you pay for.” Once you paint your pool, you will be painting it every few years, because the chemicals used to keep your pool clean break down the paint, and eventually it becomes a powder on the bottom that is continually kicked up, clouding your water. Remarciting your pool will last for years if you put the effort in to keep your chemicals balanced.