Now you can find out how much should you pay in 401 (k) fees ? Wondering how much you should pay in 401k management fees? Here’s what you need to know to avoid being nickel and dimed when saving for retirement. A good way to get started is to look at your employer’s 401(k) plan. Here’s what you need to know to avoid being nickel and dimed when saving for retirement. A good way to start managing your 401(k) costs is by knowing where you stand with a review of your 401(k) plan's “total costs” and “all in” expenses.