Didn't they already say a while back it was going to be paid for by premium content. Like extra skins for your character and items to put in your home etc... The core Home experience will be free.
*EDIT*
http://blog.wired.com/games/2007/03/interview_sonys.html
WN: And speaking of that, one of the things I wanted to ask was how do you get one of those big houses?
PH: What we wanted to show today was the sense of progression: this is the basic one, this is a more advanced one -- not necessarily the most advanced one, because it'll continue to grow from there. But users will be able to upgrade by purchasing new items, by being gifted new items from games that they purchase, and from buying items that we provide into the network ourselves as the kind of benefactor of everybody in the world. So to get the best, biggest apartment users will most likely have to buy it through microtransactions. I'm not going to get to you on your next question, which is how much is that going to be?
Yes
