looking for a device to carry firewood from the ground up to a deck which is about 10 feet high.pully system??

Farm supply, hardware store, or Lowes carries the pulleys to handle this easily. Farmers use a system like this to get hay and other stuff up into the top loft of the barn, and most farm supplies sell the parts. Hardware and building supplies carry universal rope pulleys that can do the same thing as well and are cheap. The bigger the pulley the easier it will be to pull up and the larger rope you can use as well. Also try www.harborfreight.com and www.northerntools.com if you want to simply order these type of pulleys off the internet.

you've seen those barn hay mowes at the top of the barn with the arm and pulley wheel on it, ofcourse. add a block and tackle system and you've got it.