This item is for educational purposes only. Under Federal Law no establishment may deny you equal access to goods and services based on your religious beliefs regardless of any "store policy". Unless the establishment is a private club where members must meet a certain criteria, it is a public accommodation.
42 U.S. Code § 2000a - Prohibition against discrimination or segregation in places of public accommodation
All persons shall be entitled to the full and equal enjoyment of the goods, services, facilities, privileges, advantages, and accommodations of any place of public accommodation, as defined in this section, without discrimination or segregation on the ground of race, color, religion, or national origin.