As opposed to pink and purple polka-dotted turtles? You should be more specific about the type, not just the color.
You are probably talking about a Red-ear slider.
With proper care, it will live for about 20-40 years.
Sadly, the way most people take care of them, they will die in a few months. Most people try to use a tank that is too small and cold, the wrong cheap food, etc.
If you want to learn more about keeping a turtle as a pet, try or
By the way- really cheap fish are often not kept very well at the pet shop and often just plain don’t live very long at home.
I agree with Madkins. Having an amphibian in captivity is a lot of hard work. If taken care of properly it can live for a long time.
Good Luck and Take Care
well ley me tell you turtles tend to live a long lifespan