Use a spreadsheet or calculator, or do a mental calculation.
Rate * Energy usage = price of electricity
The rate is typically given in US dollars per kWh, but it could be in any other currency
Energy Usage must match the Rate in Unit of Measurement, in this instance kWh (kilowatt hour).
1000 is abbreviated as k (kilo).
The unit for power is the watt in the MKSA systems of units. There are other units for power, such as horsepower, which could theoretically depend on the horse, but a specific had been chosen. = 745.7 W. This can be a source of error in designs that require high precision, but are distributed to different engineers.
Hour = 3600 seconds
Second is the unit of time in MKSA’s system of units. It’s the S from MKSA
This is a high school level question. Unfortunately, the USA uses a non-metric system. This can lead to confusions and errors in calculation. It has cost billions of dollars. At 14 years old, my niece is in a pre-calculus class. There’s a chapter about unit conversion and fractions. American students are 17th in international tests or comparisons because they get bogged down with unit conversions.