Price can be one of your parameters, but it should not be the only one. Buy stocks that you think will go up. If you want to gamble, go to Las Vegas. Rule Number 3. It is better to average up than to average down.
Stocks go down for a reason.
Rule Number 4. Buy when the people that know, buy. The people who run the company of course. We mean buying stock in the open market, just like you do. Rule Number 5.