you could mark all your questions on your first time through... and then do all the marked questions.
Or you could let the subscription run out and repurchase it.
(Those two ways are the proper ways of redoing Uworld)
Or you could just go through the explanations using your previous data (the questions being marked though does take away from some valuable practice)
Many of the people online, particularly on forums of other sites, are IMG's outside of the Caribbean. I know that in Pakistan/India, they have a pirated/printed version of Uworld available there that students use for their initial read before purchasing the online subscription. These students actually need the practice though because their medical education is VERY different from US education. They actually have quite a bit to learn, which is why you see the long 6 month plans on some sites using multiple reads of Kaplan and Uworld.
And then there are people who download pirated versions of Uworld from the internet.
IMO pirating Uworld ain't worth it. Just buy the real thing, twice or more if necessary, its worth it.