Ключевые слова: account, bill, bright, bulb, business, calculator, cash, cent, cheap, coin, coins, compact, concept, conservation, cost, count, currency, economic, economical, electric, electrical, electricity, energy, environment, environmental, euro, expense, expensive, finance, fluorescent, good, idea, innovation, kilowatt, light, lightbulb, money, paper, pay, payment, power, prices, save, saving, savings, services, smart, solution, thrifty, utility,