Sometimes the temperature does not decrease with height in the troposphere, but increases. Such a situation is known as a temperature inversion. Temperature inversions limit or prevent the vertical mixing of air.
Middle range machines can cost on average $400 and are often multi-function with copier and laser printer capabilities. Finally, high-end machines which offer high speeds, high capacity and high resolution come at a higher price-expect to pay $1000 - $2500 for such a fax machine.
GladToHelp is right. In this age of digital world, sending or receiving a fax thru a regular fax machine or All-in-One printer/fax/copier costs a lot more than having an online fax service like Onesuite Fax ($1/month for unlimited receiving and $2.95 for unlimited receiving and sending capability)