Everything has a cost
Nothing in life is free; "There is no such thing as a free lunch"; even "free" goods/services involves costs to someone
People choose for good reasons
people choose what they believe has the best combination of costs and benefits; decisions are not always based on caost, sometimes decisions are based on use, quality, etc.
Incentives influence people's choices
benefits offered to encourage people influence their choices; bribes, sales, deals, etc. influence economic choices
Economic systems influence people's incentives and choices
society, surroundings, resources, etc. influence choices
People gain from voluntary trade
people trade (goods, services, time, money) to gain and get something beneficial out of it
People choice's influence the value of a good or service
value is based on the demand of the product and the choices (buying and selling) made by the consumers
People's choices may have unintended consequences
people choose for good reasons, but they cannot forsee all the consequences of their choices; things do not turn out as expected
Choices made today influence what happens tomorrow
life today has been shaped by choices from the past; likewise, choices today will influence life tomorrow