AIM Calculator Commission Default Settings I noticed a $5.00 difference in the transaction cost of a BUY, the other day.
Good news, I was pleasantly surprised to see that Scottrade has reduced their LIMIT ORDER commissions to $7.00, to the same rate as their MARKET ORDER commissions.
With AIM, I am concerned with the NET transaction price per share, not just the order price.
I'm changing the default commissions of my AIM Stock/ETF Transaction Calculator from $12.00 to $7.00. If you are taking into account commissions, make sure your defaults are whatever your broker charges for limit orders.
(This is assuming you precalculate your buy and sell orders and put in GTC LIMIT ORDERS with your broker to sell some when the stock rises to your limit price, or to buy some when the stock declines to your limit price.)
BTW, I add a few pennies to the sell commission, as an estimate of what the transaction tax amounts to.