Model A is cheaper and consumes less power than the Model B.
The Raspberry Pi Foundation has announced that the Model A version of Raspberry Pi is now available for purchase in the United States. The Model A is a stripped down version of the Model B Raspberry Pi, featuring one USB port, 256 MB RAM and omits the Ethernet connectivity present in the Model B.
Of course, the fact that it's a stripped down Model B means it's also cheaper. At $25, the Model A will retail for $10 less than the Model B; it also consumes less power. According to the Raspberry Pi Foundation, you're looking at roughly one third of the power that the Model B consumes. What's more, the Raspberry Pi crew says they're working to get power consumption even lower than that.
The Model A was released in Europe back in early February 2013. At the time, the Raspberry Pi Foundation said we'd have to wait a while for U.S. availability. The Raspberry Pi Foundation told TechCrunch this past weekend that the Model A was now available to those in the U.S. market. If you're planning to get one, you can visit reseller Allied Electronics.
Talking about the Model A back in November 2012, RPF's Liz Upton said they're expecting that those buying the Model A will have different applications for the board compared to Model B owners.
"We’re anticipating that those of you who buy the Model A will be using it for different applications from Model B owners. Model A has no Ethernet and only one USB slot – and importantly, it consumes much less power than a Model B because the Ethernet chip’s missing," she said. "We're seeing demand for the Model A from people making industrial control modules, from roboticists, from people doing automation, for a bunch of headless operations – and, significantly, for people who want to use the Pi as a very cheap media centre."