In general, the MCAT won't give you a passage you cannot figure out on your own if you are willing to put in the effort. Verbal isn't about how much you know before hand, but how much you can put together in a period of time. However, the Economist is on another level; unless you know what the LIBOR is and how global quantitative easing effects the FX market, you probably won't understand the article they write on why the foreign trading volume has gone done drastically since the Great Recession (which is an article in this weeks Economist). A common misconception is that its written such that anyone who picks it up can read it; it isn't.
There are a few places you can read economics works. For the average person, newspapers do pretty well. They tend to be on the shorter side and summarize much of the points for you, but it gets you thinking about economics. The newspaper you want for this is the WSJ or, if you can get it, the FT. Both are extremely rigorous in the writing, but I like the FT's style better. For more in depth work, the posts on WaPo's WonkBlog does an extremely nice job of packaging complex ideas into digestible pieces and is on the same level as the MCAT. The New Yorker does a piece every week or so on Finance that I think is good for layman (non-economists/mathematicians/wonks). Paul Krugman writes at least 2 or 3 times a week for the New York Times Op-Ed's. He is extremely bombastic, but has a really good writing style that makes economics (or his version of it) easy to understand. Greg Mankiw is the anti-Krugman in Economic Policy but just as pleasant for me to read. All of these are read by actual economists (although to be fair, most of the people writing the pieces are actual economists).
If you need actual passages with questions and the such, the LSATs have a much higher concentration of economics passages (as well as philosophy and jurisprudence). LSAT people are probably the only group that preps more than MCAT people; they have designed websites that allow you to track and break down questions you've gotten wrong on the offical preptests (Old LSATs the LSAC releases). If you need more analysis on why you are getting things wrong and the kinds of questions you are getting wrong, you probably would benefit from the LSAT preptests. There are about 75 of them now, so you won't run out of passages anytime soon. If you run through them all, you can start working on GMAT passages. The GMAT is much easier than the LSAT and the MCAT though.
LSAT Preptests are available online, but cost $$$. If you have friends preping for the LSAT, see if you can bum a copy of some of them off of them. The WSJ, the FT, WaPo, NYT are behind firewalls, but if you are in Uni you probably have institutional access. The New Yorker is free until the end of the month online, but once again you probably have institutional access. Greg Mankiw's blog is free. If you need more free resources, I can offer you some.
Word of Caution: just reading stuff doesn't make you better at it. You have to try to be interested in it (and, at least I think it really is!), or understand why other people are interested in it. It makes reading passages a lot easier when you understand the mindset of the person who wrote the passage.
EDIT: The most helpful thing I can reccomend is to find someone who is actually passionate about something and talk to them. Don't be afraid of sounding dumb or anything, just talk. The people who write the passages on the MCAT don't write for the AAMC; the AAMC lifts the passages from various places. The one thing they all have in common is they actually care about what they are writing about, otherwise it would have never been published.
