We have the Nevada 529 - managed by Vanguard.
We were all equities till the kids hit middle school... then switched to 25% bond. My junior is now at about 60/40 bond/stock... my freshman is 50/50.
I could do age based... but this works almost as easily.
I have them in 4 funds: S&P500, Total Stock, TIPS, Total Bond.
As for fees for the Nevada plan - it starts on pdf page 31 of this doc
https://personal.vanguard.com/pdf/529progdesc.pdf
Basically - the ER (0.02-0.34) and a management fee (0.09 to 0.19) depending on the fund.
My dad started the 529's when the kids were born... He'd started in the California 529 which was managed by Fidelity but he didn't like the fees and funds. Since CA doesn't offer any tax breaks for staying in state - he switched to Nevada. It was very nice/generous of him to seed both accounts with $10k.... I miss him and loved him!