Either:

1. She likes you and thinks you're wasting your money,
2. Is lining you up as a private customer,
3. Wants you to steer clear of the shop unless you're seeing her,
4. Thinks you're beginning to stalk her,
5. She's about to scarper and is trying to let you down gently,
6. She think the boss in the shop is a cunt and doesn't want you to make him/her rich.

Any or all of the above.