Cheap Realistic Space Flight

I'm trying to imgaine cheap space flight. I'd also like to see it
sooner rather than later. Given this I believe we are limited to
chemical rockets.

What's the cheapest cost to orbit a chemical rocket is likely to
yield in the next fifty years? Will we see $100/pound to orbit?
How about $10/pound? And what underlying technology will
this rocket use?

Note: Please avoid the use of wormholes and unobtanium. Please
don't say "carbon nanotubes will solve everything" unless you also
believe that we will build 50,000 lbs structures in carbon nanotubes
sometime in the next 50 years. We're looking reasonably far into
the future (50 years or less) but trying to limit ourselves to chemical
rockets and things that can actually be built and used.