In most cases, your broker will charge a commission every time that you trade stock, either through buying or selling. May 7, at AM. Discount online brokers give you tools to select and place your own transactions, and many of them also offer a set-it-and-forget-it robo-advisory service too. Work-based retirement plans deduct your contributions from your paycheck before taxes are calculated, which will make the contribution even less painful. One of the most important fees to consider is the management expense ratio MER , which is charged by the management team each year, based on the number of assets in the fund. First of all, congratulations!