If I recall correctly, I believe that anytime she did commercials and/or ads for anything animal related, her payment was made directly to the animal groups that she supports. She had said that her money from acting was all she needed and wanted to help 'her friends'. I would find the quote but it was in a magazine many years ago.
People love Betty White for her personality as much as for her acting. She is funny, but she is also lovable. People love Betty White because she is a genuine person that really cares about animals as well as people. She has a lot of different interests and people respond well to honest actors that don't just make it about themselves.
Betty White is well known for her compassionate work to help animals. She will be honored for this work as a big part of her life. She did not have children but all her animals were treated like family. She had a long successful career and was able to use her celebrity status and income to help her favorite causes.