Spell components can be one of those things that can really add fun and flavor to a game. But they can also end up being an exercise in accounting and needless minutiae that doesn’t add that much fun to a game. And it’s all about the fun. So here’s the the little idea I’m putting together for spell components.
Generic: Normal stuff that picked up at little or no cost. Don’t even bother keeping track.
Common: Items that a character to could pick up for a few coins at a local market. Just have the character spend a few gold every time the go into town. Roughly, a number of gold pieces equal to the highest level of spell he could cast.
Exotic: Specialized things like special herbs, oils, gems or crystals and so forth. Still at this level, no need to keep an exact inventory just a gold piece amount of Exotic Components.
Rare: These are specific items. Here’s where you keep exact inventories. Prices will vary wildly depending on the item. Ingenious players will also start using the bits and pieces of special or particularly nasty monsters for components.
Unique: These are really MacGuffin type items. There’s only one of them in the world. It’s use is powerful and a one time thing.
Now bending this little bit into the rules.
If a spell states that you need X item (like 1,000 GP worth of Diamond Dust) then you still need it.
Generic and Common spell components are just a cost of being a spell caster. Nothing special here.
Exotic: The character uses up the spell level times 10 GP worth of exotic components then spell is empowered by a factor of one in a way that makes sense for that spell. An extra die of damage, -1 to a saving throw, extra duration, whatever makes the most sense. This may cause a little haggling with the DM but players ask before you cast.
Rare: Allows the caster to cast an unprepared spell that thematically fits the component. The caster must know or have access to the spell. Additionally, the caster must successfully make a Saving Throw versus Magic for the spell to succeed. The component is consumed in the casting whether the caster successfully casts the spell or not.