Cost Formula for Metamagic Rods

[Tequila Sunrise]

There has to be one because quite a few of them involve fractions of 1,000 gp; if the prices were just a 'ballpark' they would all be in flat thousounds of gp, if not tens of thousands. Does anyone know what it is?

 

[Cheiromancer]

I'm aware of this thread: Reverse Engineering Metamagic Rods. The formula is quite complicated.