Hi AiredaleLover,
Most pet stores that sell small animals such as birds, fish and hamsters will also carry turtles and turtle supplies.
They are pretty easy to care for. You can get turtle food (little pellets that you put in the water) for them and supplement their diets with a variety of vegetables, greens and fruits. My turtle, Yertle loves tomato, lettuce, strawberries, spinach, cabbage, etc.
My turtle roams the apartment, but most people have them in a tank with rocks and a whole setup.
If you check the posts here, you'll find several threads about turtles, Ben even posted a picture of his turtle tank somewhere. It's really cool.
Good luck and let us know when you get your turtles!