To "be in someone's shoes" is an idiom meaning to be in someone's position. Usually used hypothetically. https://en.m.wiktionary.org/wiki/put_oneself_in_someone%27s_shoes http://www.dictionary.com/browse/in-someone-s-shoes

$655 is a lot to pay. $10,000 is a huge deductible, which is also bad. She is saying her life sucks. We try to understand people by imagining 'walking in their shoes.' She is welcoming you to walk in her shoes to see how stressful paying so much money is. However, this is figurative, so she is asking you to imagine paying that much money.

it means that she (the person who is the speaker talking about) is now in the same position/condition as the speaker. they have similar or even the same issue

Welcome to my shoes doesn't make much sense. I think what that line is trying to say is "Welcome to my life"

Thank you for your explanation. It's so much helpful for me.