Even though some may not have thought there would be room for a downgrade of the Raspberry Pi, the Raspberry Pi Foundation has its own opinion.
Here is the Raspberry Pi Model A, almost identical to the Model B but equipped with only 256 MB of RAM (B has 512 MB) and one USB port (B has two).
Most interesting is that the Model A completely lacks Ethernet connection, meaning it can't be used as a Smart WEB TV creator.
It should, however, be a cheaper ($10 / 7.68-10 Euro cheaper) means of creating mods and gadgets, like a certain pocket-sized MAME arcade cabinet. The lack of an Ethernet chip significantly cuts power use as well.
“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 center,” Liz Upton wrote.
Raspberry Pi Model A Complete, Shipping Now
It has lower specs than the Model B, but is $10 cheaper (7.68-10 Euro)
... so hot right now