Everybody has a favorite smoker fuel, and it's a pretty popular topic among beekeepers.
I have had luck with a couple of things: The fiber plugs from Dadant. They are cheap, and produce cool smoke a long time! Great for multiple inspections. The problem is, it literally takes a blow torch to light them, and the smoke isn't terribly thick. Great once they're lit, though.
And I ordered a pound of burlap off ebay for a dollar. The shipping brought it up to nine dollars, though! :? It lights easy, has pretty thick smoke, stays lit a good long time. Not as long as the plugs, but it's good for three hive inspections, at least!
And you don't think 1 lb. of burlap is a lot, but it IS! It was about the size of a laundry sack.
(I love the smoke that pinestraw produces, and you can't beat the price, but it produces really hot smoke, and can blow hot sparks... Maybe I'm packing it wrong, though.)
What's your favorite?