I've been working for Costco for the past couple months and honestly I'm incredibly grateful to be working for them.

Even though not every location is affiliated with a union, the entire company is run as if it were a union anyway. Sundays are automatic time and a half, and after 1,000 or so hours worked you get a raise (Sundays also count towards 1.5× hours worked as well). Plus my coworkers are all extremely nice and polite; like moreso than literally anywhere I've worked before. Plus we get benefits (health, vision, hearing, etc.) even as a part-time employee.