$500 divided by .0116 (current price) = 43,103 shares of SFOR. Of course you need a few extra dollars for the cost of your stock trade with your broker (usually $5-$7). I use Etrade for penny stocks.

When buying, you need to watch the current price on on the ask for SFOR (with some trading software) and try to buy at that price, or wait till the price goes down. For example, the ask price is now .0125. If you put in an order at .0116 you could wait and see if it falls to that price (and your order might go through) or you could change your order to .0125 (a higher price) if you want to buy now.

I use only limit orders when I buy. That means you put in a specific price on your order where you want to buy (e.g. .0125). Don't use market orders to buy or sell, as they might get filled at a much higher or lower price than you want.

I hope this helps.