If it is May 1st and I have $1000 to invest, and after due diligence, I like a stock which sells for $99, I might buy 10 of them at the market price and pay $10 for the commission. Assuming the stock has good volume and I end up getting it for $99, I will end up with stock worth a total of $990. (This technique will not work for stocks which do not have good volume because the actual sale price will be very different from the market price. I am not a sophisticated investor so I stick with stocks with large volume.)
Because of human psychology, I now face two risks:
In both cases, I'd be wrong and that's that's why most investors lose money.
To reduce these risks, once I own the stock, I will immediately decide my target price and tolerance for potential loss; and I would like to place the following orders which are good for 30 days:
Certain brokerages do not allow these so-called "one-cancels-the-other" or "bracket" orders. Scotia iTrade does not allow them, but Questrade seems to. See also this StackExchange thread.
If I check my portfolio every month, then on June 1st one of these scenarios will have played out:
More about order types can be found on the YouTube video "FRM: Order Types (market, limit, stop, stop-limit)".