It's a valid type of store/shop in the U.S.  Here's the definition:
thrift store
noun [ C ]
US
uk
/ˈθrɪft ˌstɔːr/ us
/ˈθrɪft ˌstɔːr/
(also thrift shop)
Definition: 
a shop that sells used things such as clothes, books, and furniture, typically in order to raise money for a charity

https://dictionary.cambridge.org/dictionary/english/thrift-store