A lot of embedded systems are free. We create a Lab and run some popular embedded systems on virtual system. You can port new system middle ware even if you do not have any hardware. eCos on Synthetic eCos on MINI2440 QEMU RTEMS on MINI2440 QEMU
The Open Instrumentation Project provides open source software for graphical user interface and control of computer-based lab instruments. Current instruments include an oscilloscope, waveform generator, CircuitGear, multimeter and network analyser.