This whole question seems to be a solution in search of a problem.
Since cost was mentioned, we really need to take a serious look at it. Spirit and Opportunity cost about $500,000/kg to make it to the Martian surface. The lunar module ascent stage weighed about 2000 kg without propellent. So that's a billion dollars right off the bat.
The LM had about 4.5 habitable cubic meters for two people. You can't put people in a space that small for 450 days, so let's say that the astronauts share a space the size of a Supermax Prison cell. That increases the volume by 4.2, and assuming the mass goes as area, the cost by 2.6. So we're at 2.6 billion.
The reliability of Mars missions is about 2/3, and manned missions is >95%. A good rule of thumb is that reducing the failure rate by x requires an increase in cost by x. If you're willing to go with a 90% success rate, that gets you to $8.7B. So that's a guess what it costs to drop two guys in a tin can on the surface of Mars.
The problem is that you can't just drop two guys in a tin can on the surface. You need to send a rocket so they can get back. A Delta II weighs about 200,000 kilograms, so you're talking hundreds of billions.