I think the original poster will have a very difficult time, if not impossible time, getting into the field in anything other than the lowest, least skilled position (with commensurate pay). Just knowing C++ is not enough to break into the field in a few months.
I think in general the post is true. If you cannot have the luxury to work all day on something relevant about the field, you cannot be prepared for a real job in months or a year.
Please notice that your computer is not just a processor, so when measuring performance of the processor/dollar then please use the performance/whole-machine formula instead.
However if you use your machine for io-intensive tasks, the question is bad for you. Anyways this way of calculating is simply not correct. If you are a quantum-mech scientist maybe... even my eclipse building my java code eats the hdd not cpu.