Good luck, sarahrachel! My dad was a store manager for a long time, and hated to do interviews. He said he would ask questions, but the specific answers were not all that important. He wanted to get the impression that the person was hard-working, dependable, and trustworthy.
Another answer to "why do you want to work here?" - If it's a store you shop at regularly, a great answer is, "I love this store!"
I hope you let us know your results.