How to pull discount rate from if statement

I need to calculate the total purchase price of the books. The discount is determined by the amount of books purchased. Those are split within the if statements. How can I have my code fully work is currently is giving me this error message:

BOOK_PRICE = 100
def main():
    numBooks = int(input("Enter the number of books you will be purchasing: "))
    eligibleDiscount(numBooks)
    totalPrice(numBooks)

def eligibleDiscount(numBooks):
    if numBooks <= 0 and numBooks <= 9:
        print(" ")
        print("Your TOTAL PURCHASE PRICE is: $ ",totalPrice)
    if numBooks >= 10 and numBooks <= 19:
        print("Since you are ordering",numBooks,"books you will receive a 20% discount!")
        print("Your TOTAL PURCHASE PRICE is: $ ",totalPrice)
    if numBooks >= 20 and numBooks <= 49:
        print("Since you are ordering",numBooks,"books you will receive a 30% discount!")
        print("Your TOTAL PURCHASE PRICE is: $ ",totalPrice)
    if numBooks >= 50 and numBooks <= 99:
        print("Since you are ordering",numBooks,"books you will receive a 40% discount!")
        print("Your TOTAL PURCHASE PRICE is: $",totalPrice)
    if numBooks >= 100:
        print("Since you are ordering",numBooks,"books you will receive a 50% discount!")
        discountRate = .50
        print("Your TOTAL PURCHASE PRICE is: $",totalPrice)

def totalPrice(theTotalPrice):
    subTotal = (numBooks * BOOK_PRICE)

    discountPrice = (numBooks * discountRate)

    theTotalPrice = (subTotal - discountPrice)

    return theTotalPrice
main()