She earned $10.00.
Step 1: Begin with the amount they had left: $2.74.
Step 2: Find out how much they spent.
Step 3: Add the amount spent to the amount they had left.
Step 4: Subtract the cost of the exercise wheel they returned.
$15.00 amount brought to the store
Step 5: Subtract the amount of money Lee contributed.
Nicki had earned $10 last week.