When I've seen firewood for sale in or near campgrounds, it has usually been for $5 to $10 per armful, pretty expensive for a guy used to buying his firewood by the cord (we heat with wood).
But I recently sprang for some ecoblocks just to test out the product.
These are blocks of compressed, kiln-dried sawdust. They are compressed to about twice the density of cordwood, and are very dry. While more expensive than cordwood, they are cheaper than those armful bundles of firewood, costing around $3.50 for a pack of 6. In an open fire, each brick burns for about 90 minutes, they burn pretty smokeless, since they are very dry. They are also bug-and-pestilence free.
I'm kinda thinking next time we go camping, I'll carry along a few of those things . . . .