FYI, the original version of improved metamagic (which you can't possibly take till L30 due to skill requirements) lowered the cost of all metamagic feats by 1, to a minimum of 1.
This was revised in 3.5 SRD. Now it lowers the cost of any spell to which a metamagic feat has been applied by 1. That is, if you apply 3 metamagic feats each with +2 costs, the total cost is +5 (rather than +6 without the feat, or +3 with the original version of the feat).

