american
background
banknote
broken
bulb
business
capital
cash
cent
change
coin
coinage
coins
commerce
concept
conservation
cost
currency
dollar
earn
economy
efficiency
efficient
electric
electricity
energy
equipment
exchange
finance
financial
fluorescent
glass
idea
illuminated
innovation
investment
isolated
lamp
light
meter
modern
monetary
money
old
paper
pile
power
save
savings
solution
supply
symbol
technology
usa