from collections import Counter

prices = {"course": 97.99, "book": 54.99, "wallpaper": 4.99}
cart = Counter(course=1, book=3, wallpaper=2)

for product, units in cart.items():
    subtotal = units * prices[product]
    price = prices[product]
    print(f"{product:9}: ${price:7.2f} × {units} = ${subtotal:7.2f}")