If somebody is having a garage sale you could get a second hand one.
The average price for a popcorn machine can range from very low to very high. This depends on how big or small the machine is that you plan on purchasing. They can range from $100-$400.
Because there is always going to be friction, the efficiency of any machine will always be less then 100 percent.
No. A perfectly frictionless machine could have an efficiency of 100%. Anything less perfect must have can efficiency less than 100%.
No. A simple machine such as a lever could quite easily give a mechanical advantage of 10, 100 or more, or could even be less than 1.
No, there is not such thing as an ideal machine; it's just an idea.
Yes. Cheez-it has 500 calories (100 grams), popcorn has 387 (100 grams)
100
True.
Less than $100
the efficiency of any machine is NOT 100% because some of the input work is used to compensate for the work done by friction.
If you mean 1600 pounds, then no. That would be 6.25 pounds of popcorn, since there's sixteen ounces in a pound. :)
It is the output energy compared to the input energy. This will always be less than 100%