"There's a pretty general consensus that one of the greatest barriers to the exploration and development of space is the cost of launch to low earth orbit"
http://www.fourmilab.ch/documents/rocketaday.html

I would say roughly with economy of scale of hundred or two launches per year you could get a launch price of $500 per lb for Low Earth orbit and $1000 per lb for High Earth Orbit and/or Escape. Current prices are about $3-4000 per lb for LEO and $8000 for High Earth Orbit/Escape.

I would say that if you had on order of scale hundreds of launches per year for a decade or more you could get to around $100 per lb to LEO, but that's about as cheap as it gets using chemical rockets and throwing away the hardware each launch.

But we aren't really looking at a mature market when we look at market of hundreds of launches per year, compared to say the airline business. Suborbital trips are about a 1/4 to 1/2 of what it takes to get to orbit. I believe the ticket price for a suborbit trip is going to be about $100,000 per passenger- roughly $500 per lb with idea that evenually this could get around the $5,000 per passenger in a maturer market [1/20th of current price so it's $25 per lb for suborbital]. This "route" could lead to $50 per lb to LEO. But all this is a bit like predicting the cost of car travel at the beginning of 20th Century.