Well, Princess Crown is a really tough one to find. I don't think I've seen anyone else sell that CD on YJA. On Amazon, there are four copies for sale, starting at 78,000 yen (though I think they're all sold by the same person). On Liberty's game CD list, this is the one album that hits 20,000 yen (though I don't know if that's the price they're willing to pay, or the standard price when they sell):
http://www.liberty-shop.co.jp/kaitori/gamecd.htm