i need to do sap sd certification ,training for same is very costly from authorised center and i canot afford ,the other way is i do training from unauthorised center and take certification exam in any country where prerequisite is not doing training

i need to do sap sd certification ,training for same is very costly from authorised center and i canot afford ,the other way is i do training from unauthorised center and take certification exam in any country where prerequisite is not doing training from authorised center.how good it it to do prepare from unauthorised center and take exam in any country like australia ,US ?please help understand .