SpaceX's Mars ships won't be ferrying just the super rich to and from the Red Planet, if everything goes according to Elon Musk's plan.

The price of a seat aboard SpaceX's Starship interplanetary vehicle will eventually drop enough to be accessible to a large chunk of the industrialized world's population, the billionaire entrepreneur predicted over the weekend. 

"Very dependent on volume, but I'm confident moving to Mars (return ticket is free) will one day cost less than $500k & maybe even below $100k. Low enough that most people in advanced economies could sell their home on Earth & move to Mars if they want," Musk wrote on Twitter Sunday night (Feb. 10). [Images: SpaceX's Giant Spaceship for Mars Colony & Beyond]