My 73 year old mother got a White Shepherd. She has problems with the dog jumping up and also nipping at her shoes while on walks. Would a shock collar help?

Hi My mother got a white German Shepard.She is 73 years old and lives alone.She wanted the dog for protection to let her know when someone comes up.She has a problem with the dog jumping on her and skinning her arms up. and nipping at her shoes. When she walks.She wants the dog but I don't think she can handle him.He's a smart dog. I thought about getting a shock collar. I have seen some from 90.00 to 450.00.I don't know which one would be best for her. She is on a fixed income. any help would be thankful.

Kim