The costs that you use are much lower for initial trials in mining, even to meet the needs of standard working tools requires a much larger capital, not to mention talking about the cost of available electricity and maintenance of equipment in the event of damage.

Not the fastest way to generate BTC assuming a capital of $ 300, it's better to buy directly and try to survive in the next period of increase and you can try to raise capital first before being interested in trying to mine. I've seen how many people eventually have to quit because they can't afford to pay for equipment maintenance and so on.