I like where the discussion is going on Low End Walmart bikes. To provide an interesting prospective, check out this article in Bicycling Magazine. It highlights a part of the cycling population that we not only fail to recognize, but often are oblivious to.  It's kind of long but a worthy read.  
 
http://www.bicycling.com/article/1,6610,s1-3-12-13639-1-P,00.html