As mentioned, she wishes to purchase a bicycle every week. She needs to save $10 each week, which changes the meaning since the writer wants you to know or remember that she has to save $10 per week in order to accomplish her objective of buying a bike every week. make this like a 6th grader wrote i

She really wants to get a new bike every week, and to do that, she needs to save $10 every single week. This means that she has to set aside $10 from her allowance or any money she gets each week, so she can buy a bike regularly.