I want to insert my five cents. As already written, for training, you really do not need a phone in the gland. To develop a phone, you need all sorts of sensors, SMS notifications do not all come, graphics slow down, etc. But for $ 250 it will not be a very good android, to put it mildly :) I am writing a network toy for fun, so I have two phones with different firmware, one is $ 600, the other is 800. And another tip: write to Linux on emulator, I have the laptop is four years old, with ubunt on it, core 2 duo 2.4Ghz, 3GB DDR2 and works quite well. Although it may be my cockroaches, for me things should be either free or not cheap.