NASA designed liveable space colonies in the 70's, solving most of the issues back then, it's just that they're way too expensive to build.
However, seeing that we're entering the age of commercial asteroid mining, the issue of getting resources into space from earth will soon (i.e. some decades away) be circumvented. As well as construction materials, this would also provide an abundance of cheap water (which = life and rocket fuel).
Why would they be more expensive than creating a colony on mars? If we're talking about making a mars colony, I feel like alternatives being prohibitively expensive goes out the window.