THE PRICE IS RIGHT: Audrey Watters calls to attention Mathalicious' 2012 pricing plan: pay what you can. On its blog, co-founder Karim Ani shares his thoughts on the foolishness of settling on a fixed price when his company's goal is to maximize users. So he's added three subscription plans--$5, $10, $15 per month--in addition to Mathalicious' standard rate of $20 per month. "Every plan is exactly the same. The only difference is how much teachers choose to pay." It's an experiment: we'll let you know how it goes.