States often charge a one-time account setup fee for a 529 plan. These have ranged from as little as $25 (in Florida) to $964 (in West Virginia) for the lowest-cost option. In addition, if you bought your 529 plan through a broker or advisor, they may charge you as much as 5% or more on the assets under management. The individual investments and funds that you have inside of your 529 may also charge ongoing fees. Look for low-cost mutual funds and ETFs to keep management fees low.