In the universe of 401(k) plans, small plans outnumber very big ones — but big plans have all the money. With more participants to shoulder fees and more negotiating clout, people in plans with more participants and more assets pay less for their retirement plans and leave work with a bigger nest egg.The graphs in this story break out the types of plan fees according to the “401k Averages Book,” which draws from a database of 182 products from 64 providers. The average account balance for each of the plans depicted is $50,000. Want to know what fees could be included in your plan? Read on to learn about the types of 401(k) fees people pay per year and how they vary from small to large plans.