Item Creation Confusion

[kreynolds]

The spell affect has been added to a Quiver of Ehlonna.

Oh, I remember this!

 

[dcollins]

The spell affect has been added to a Quiver of Ehlonna. 50 +3 arrows are expensive... more cost-efficient to use regular arrows.

May I quote Monte Cook? (http://www.montecook.com/arch_dmonly3.html#marketvalue)

The most important thing to remember is, Table 8-40 doesn't determine prices. It suggests them. Don't say, "Wow, these shoes of continual improved invisibility sure are cheap." Do say, "Hmm, these formulas don't work when it comes to spells like improved invisibility."

If a proposed new item is more "cost-effecient" than the existing magic solution, then it is by definition broken and should not be allowed by the DM.