There's a fairly comprehensive introduction to it here:
http://finallyfeminism101.wordpress.com/2007/03/11/faq-what-...
"Since social status is conferred in many different ways — everything from race to geography to class — all people are both privileged and non-privileged in certain aspects of their life. Furthermore, since dynamics of social status are highly dependent on situation, a person can benefit from privilege in one situation while not benefiting from it in another. It is also possible to have a situation in which a person simultaneously is the beneficiary of privilege while also being the recipient of discrimination in an area which they do not benefit from privilege.
Male privilege is a set of privileges that are given to men as a class due to their institutional power in relation to women as a class. While every man experiences privilege differently due to his own individual position in the social hierarchy, every man, by virtue of being read as male by society, benefits from male privilege."
That's just male privilege, you get others from class, sexuality, religion, health etc.
Also, I knew some 'very poor' kids who had these machines. Funny, I don't remember them being expensive (but what did I know; I was 8 ;) Maybe they were; I'm too lazy to research it.