There are 8 oz in a pound (lb.) So, if there is 1 lb (8 oz) and 4 oz, then you have a total of 12 oz. Since it costs $0.45 per ounce, then you would multiply 12 times .45. After that, you would convert your answer to money by adding a dollar sign and a zero after the last number.
Work:
12*0.45=5.4
5.4=$5.40
Final Answer: $5.40