Mine are a 1/2 and 1/2 mix of poplar and birch. We really only have 3 woods here, spruce being the other. Spruce I don't like for campfires, it spits and pops a bunch and the embers put holes in chairs, shirts, tents or worse... sets the woods on fire!
I'd say 1 cu ft is about the biggest I'd go in a bundle of that wood and be light enough that most people can easily handle it. It's in the area of 25-30lbs.
Didn't mean to put numbers as a manhood measure contest thing, just gives an idea of what can be done. I know if someone said they could do let's say 50 an hr, I'd be asking questions to try and improve my systems.
Quanities and prices really will depend on the area. I know some folks in other parts of the US are able to get $10-12+ for a bundle and sell the heck out of them. I wouldn't be able to do that, have to stay priced roughly with the competition. Tough to compete against the gas station or grocery store just on the convenience. People get supplies for the camping trip and the wood is just one more thing they can check off at 1 stop.