DIY Foaming Hand Soap

I recently made the conversion over to foaming hand soap from the usual gel formulation. It spreads easier; it washes off better; and the five year old in me loves the bubbles. An article that I read months ago said something about it being better for your pipes as well. Unfortunately, each pump pulls out a greater volume — try both dispensers and you'll see. Why does this matter? Cost.

I'm a little obsessed with eco-friendly products and conservation, so two of my favorite product lines are Method and Seventh Generation. Method has a wide array of scents and colors, but 1 litre of gel hand wash costs the same amount as the foaming solution, and both are significantly costlier than, say, Softsoap. This presents a good place to cut a few corners.