Formations vs. Play's

I get asked by coaches all of the time how many play's are too many?  Most high school coaches think we run tons of plays along with division 1 team.  I believe there are two types of styles you can use.  The first is a team like Stanford who uses 350 plus play's and can call any play at any certain time.  However they do not use a significant amount of formations and obviously they are at Stanford for a reason usually not for their dreams of going to the NFL.  The second would be Fewer plays and a lot of formations.  Formations are very cheap, meaning they usually don't cause confusion with players they only need to remember where I am on this particular formation.  However play's are expensive, not for everyone in the offense but for linemen, the QB and RB have multiple things to think about on any particular play within any look they may see from the defense.  These types of offense usually are spread teams.  The last fits into this category as well Few play's with lots of shift, Motions, and formations looking different week to week while running the same play a la Boise State.