Metamagic feats that reduce required spell slots

[SinsI]

If any of these feats would reduce the required spell slot to lower than 1/2 of the actual spell level (rounded down), they reduce it to that level (1/2 of actual level, rounded down) instead. (0-th level spells stay 0-th level)

Shrink Spell (Metamagic)
Benefit:
You can alter a spell with a range of short, medium or long to reduce its range. A shrunk spell that initially had a short range (50 ft + 5 ft./level) has a range of close, medium-range spell (range of 200 ft. + 20 ft./level) becomes short range and long-range spells (800 ft. + 80 ft./level) become medium range. Shrank spell uses up a spell slot one level lower than the spell’s actual level.
If applied together with Enlarge Spell, these feats cancel each other.

Shorten Spell (Metamagic)
Benefit: You can reduce the duration of a spell with a duration of longer than 1 round by 50%. Shortened spell uses up a spell slot one level lower than the spell’s actual level.

Decimate Spell (Metamagic)
Benefit: You can alter the duration of a spell with a duration of 1 minute or longer. Decimated spell has its duration reduced by a factor of 10.
Decimated spell uses up a spell slot 2 levels lower than the spell's actual level.
Special: You can apply this feat to the same spell multiple times, as long as the final duration is at least 1 round. Each use of this feat after the first reduces required spell slot level by 1 instead of 2.

Minimize Spell (Metamagic)
Benefit: All variable, numeric effects of a spell modified by this feat are minimized. Saving throws and opposed rolls are not affected. You can only apply this metamagic to spells with random variables. A minimized spell uses up a spell slot three levels lower than the spell’s actual level.
If applied together with Maximize Spell, these feats cancel each other.