Typically once or twice a year, the Kimberly Clark corporation opens up their website where you can sign up to receive extra coupons. They are always really good ones! I'll warn you the site is in Spanish but here's a useful guide posted on HCW:

Nombre= first name
Apellido= last name
Dirección= street address
Ciudad= City
Estado=State
Código Postal=zipcode
¿Cómo escuchaste de nosotros?= how did you hear about us?
Correo electrónico= your email address

Sign up here: Qué Bueno es Ser Madre y Mujer