Having well seasoned firewood is important to ensure it burns well and cleanly, this means that the timber is dry i.e Not green. Firewood that is seasoned will catch alight more easily, burn hotter and keep your chimney cleaner with less soot build up.
A ton of firewood in terms of volume is roughly 2 cubic metres. This will vary depending on the particular type of timber as they all have different weights. In terms of cost for a ton of firewood this can vary greatly depending on demand, type of timber and area generally it will be in the range of $250-$350 a ton.