http://www.biffy.com/cart/index.php/bidets/biffy-universal-bidet.html
I figure it paid for it's self in about 6 months. I have the ambient warmer and a dozen hand towels (one for the Mr. and one for me) that i throw in the laundry often.
edit to add
Installing bidets in your home is a home improvement that has wide-reaching effects and greatly impacts waste reduction while simultaneously improving personal hygiene and health. When bidets are routinely used by every household member, the amount of toilet tissue and pre-moistened personal hygiene wipes that does not go into our sewer systems is substantial.
How substantial?, you ask. Well, many experts say that the bidet is a key green technology because the bidet can potentially eliminate the use of toilet paper. According to independent studies, Americans use 36.5 billion rolls of toilet paper every year, representing the pulping of some 15 million trees. That equates to 473,587,500,000 gallons of water to produce the toilet paper, and 253,000 tons of chlorine for bleaching that paper. Factor in the statistic that says the manufacturing of the toilet paper requires approximately 17.3 terawatts of electricity annually, and that significant amounts of energy and materials are used to package and transport the final product to retail outlets. Keep in mind that the packaging must also be disposed of. To those who claim that a bidet will waste water, proponents counter that the amount of water used by a bidet is menial compared to how much water we use to produce toilet paper in the first place.