This is a post I've been meaning to write for a long time, now. Since my "switchover" to Organic, I have found many things that actually IMPROVE my budget! One of them is homemade soap. I don't make it myself, mind you, I find someone local who is already outfitted with the skills and materials, and purchase from her! Recently, a farmers' market vendor has satisfied all my needs. The bars are about the size of a computer mouse (I'm unsure how many ounces that is), and made of completely pure, biodegradable, organic ingredients. I was even able to find one for my kitchen that is anti-microbial. (Rosemary and tea tree work quite well for fighting cold germs and kitchen scum.)
The best part of bar-soap is that is ENTIRELY cost-effective! I spent $4 per bar, and expect each bar to last at the very least, 1 year. With just 2 of us in this household, I wouldn't be surprised to see them still around 2 years from now. They're just as gentle as your creamiest shower gels, too, and you can even buy ones made from glycerin, tempered further with oils, butters, and natural essences of all kinds. The scents are usually more "earthy", which, for me, is a bonus. I tend to favor things that smell somewhat "green" rather than the thick, floral smells from commercial perfumiers.
Another added bonus: the packaging waste presented by bottles and bottles of shower gel (however many you purchase in a year's time) is completely absent in bar soap. If the homemade soaps come wrapped at all (some are just sold out of bulk boxes, fresh-cut from a slab), it is usually a bit of brown paper or a sticker or ribbon. Far easier to return to the soil than a plastic bottle.
So, we are "back to bar soap" these days, enjoying the earth-friendly, pocket-friendly aspects alike!