No one dies if they use Rinne Tensei alone.
Nagato had like 1% chakra left... and used all his remaining chakra to perform Rinne Tensei.
You die if you get 0 chakra...
edit;
as quoted in naruto during the chunin exams when Kakashi was training Sasuke, he told sasuke the following:
"well you're good for about 2 blasts", refering to chidori.
then Sasuke said, "what would happen if i try a third time?"
Kakashi answered "if you try to force a jutsu, not only will it not work... you use up all your chakra and in the worst case scenerio, you will die"
also;
Rinne Tensei seemingly requires a massive amount of chakra, risking death in the process, as Konan feared the worst for Nagato when he used it after having previously expended so much chakra. After using the technique, Nagato became severely weakened;
his hair became white due to overexertion of his chakra. (which is why he died)
and this mustn't happen every time you use Rinne Tensei!