Can not beat good old fashioned god given WOOD! Plentiful and flexible, most ALL lumber stores have scrap pieces that they will give you!! Just ask at the lumber counter,,WE have a Redwood Lumber yard close to us,, i was purchasing some fencing and mentioned I could use a few small 2x10 or 2x8's, The lumber guy asked how long,, I said 24" to 36", told me I could have anything I found in there scrap bin next to there cut saw,,, I have enough for myself and a buddy... Doesn't hurt to ask!!
P.S.we happened to buy wood from a camp host,,it was damp wood and hard to start,, I sacrificed a few on my 2x10 levelers and got a good fire going!!