a day at the mall

It is Saturday . Saturday is shopping day in my family. There is a big department store near my house .The store is having an anniversary sale, and everything is half price . My mother says “It ‘s a beautiful day .It’s time to go shopping, Lucy ,are you ready? we ‘ll start out .” “yes, I am ready now. ” Then we go to the big department store.

"lucy ，What do you want to eat for supper ?" 
"I want to eat fish and tomato. " 
"Ok, we can buy some fish and tomato." 
But Mother and I can not find the fish in the store. Then a salesman comes to us .She says "Can I help you?" 
"Yes, where is the fish ? we want to buy some fish."
"Over there , in that corner."
"Are there any tomatoes in your store ? "
"Yes , there are. The tomatoes are near the fish."
"Thank you."
"You are welcome."
Then mum and I find the fish and tomatoes in the corner . 
"Lucy ,Would you like a piece of cake?"
"Yes, mum ,Please buy a piece of cake for me"
"Ok."At 6:30, we go home.. 
"Mum I like shopping , I like Saturday."

? Questions: 
（ 1 ） When does Lucy's family usually go shopping? 
（ 2 ） Why does the department have everything half price?