If it is well written and about you, anything can be a good topic. After attending admissions information sessions at almost all of the elite colleges in the country, it is clear to me that the admissions officers are sincere when they say they want you to write about you.
Echoing @BB excellent thoughts in #18, If you write too much about the actual thrifting, and not enough about yourself, your essay could run the risk of the AO reader thinking - “well, I learned a lot about thrifting, but really not much about this applicant…”
But using this topic as a basis for something that you’re passionate about, could be a great way to tell them who you are.