In reply to JD84:
If you live near an industrial estate you can usually get free pallets.A lot of places leave them outside to be taken free so they dont have to pay for disposal. They burn fast but the blocks at the corners last longer.
Very dry and easy to chop up. No need to bother removing the nails just put a magnet in a plastic bag and pick the nails out of the ash easy peasy.
Granted they aren't as long burning as hardwood but they are free.