Did you know that there are also adoption organizations out there? Here's a link that may help you find one:
www.turtlehomes.org
Shipping live turtles is not encouraged. It's very hard on the turtles. Best if someone can pick them up.
Are you also offering equipment? That's important as the setup for a slider is pretty involved.
Please carefully question anyone who responds and make sure they are responsible enough to care for aquatic turtles and have the means to support a good environment and provide vet care if needed. Make sure they know what they are getting into!