There shouldn't be...
I don't know if there is such a feat, but if there is it should not be allowed. One of the oldest ideas in D&D is that rare and/or precious materials are better at handling magical energies, because of their particular purity and/or properties. To substitute other, cheaper materials violates this principle. Any Metamagic Feat would wind up trading a lower cost for a higher level spell slot. I don't like this idea at all, since the higher level spell you use, the MORE magical energy you are directing. It seems logical (if magic can be so) that the materials needed for a higher level spell would need to be more pure/precious than the original. Trading levels for extended range, duration, damage, lower casting time, or less chanting volume are all functions of the spell energy involved, whereas the feat you seek would instead be a trade of level for physical material. The logic is different. An alternative might be to ask the DM to allow that expensive materials not be consumed in the casting. There is lots of precedent for this in the game already, as well as in the older versions. All you would be asking for is an expansion of when this "non-consumption" rule applies. Is that a fair compromise? ~O~
