If we could do it with purely electrical motors, then assuming you pay 10 cents per kilowatt hour and only have a conversion efficiency of 75% into actual lifting power, it would only cost you $0.04/kg energy-wise to get up there. Assuming that you'd need to take an environment of, say, 10,000 kg with you, the marginal cost would still only be about $400. That's something of an ideal case, the "space elevator" proposal. Actually there might even be a possibility to use counterweights somehow to make it even cheaper.

Solid rocket fuel, the numbers are a little harder to come by. It sounds like the active ingredient is usually aluminum. One page on Wikipedia suggests that aluminum has an energy density of 31 MJ/kg (and my calculations based on Wikipedia's "aluminum oxide" page agree) and that only 16% of solid rocket fuel is aluminum. So that's 5 MJ/kg. However, this is a little smaller because it basically needs to push itself up along with you -- it's 1 MJ/kg to bring anything up to space, remember, so 1 kg can lift roughly 5 kg of stuff, but the 1kg of fuel is itself part of that 5 kg. So we're at roughly 4 MJ/kg if you take into account that the fuel more or less has to push its own way up with you. (Not all the way, of course, but I'm too lazy to do the calculation properly and there's wind resistance anyway.)

The first rocketry site on Google says that they'll sell you 20 pounds of rocket fuel (9 kg) for something like 200 bucks, or $22/kg. With the conversion factor of 4 kg lifted / kg fuel, the equivalent number is about 550 times higher -- $5.50 per kg that you want to send into space, and the marginal cost for our 10,000 kg environment is presumably then something like $55,000.

Can we do better by bulk? Google says people sell the main ingredient -- ammonium perchlorate -- at $3,000 per metric ton. Aluminum is a bit pricier, but I can find people selling large chunks at about $500/50kg, adding about $1,500 to the above. Adding in the cost of the plastic binding, the raw fuel components might cost $5/kg. So you're not going to get cheaper with rocket fuel than around $15,000 per flight.

Of course, the spacecraft is going to be the more expensive bit, I'm sure. But that's more complicated because maybe you can amortize that cost over many successful runs. I'm just saying that, even without that, based on fuel alone, it's still going to be an order of magnitude more expensive than a trip to a far-off land. If we had a space elevator we could fix that, maybe -- but not without a massive cord going from us to outer space.

I will add that you can make these numbers cheaper if you don't go into the 'official' outer space region, but just content yourself to fly really high up. People who fly weather balloons can get them to a height where you'd need closer to 0.3 MJ/kg to get to, so you could divide those costs by ~3.

Here is a link to one group that is trying to solve the problem of cheap amateur rocket flights to space: http://www.copenhagensuborbitals.com/

One of the reasons the Concorde never really succeeded was due to the nature of faster than sound travel. A sonic boom doesn't just happen as you pass the sound barrier, but rather trails behind an aircraft the entire time it is traveling over that critical speed. This resulted in the Concorde only being able to travel faster than the speed of sound when it was over water (hence it's primary use for travel between New York and Paris or London).

But what if you could travel where there is no air?

Suborbital space flight means that any place on the globe is a 2 hour flight away. This will happen, and I am confident that I will travel in space before I die.

http://www.celestis.com/services.asp