Simple Q&A D&D 3.5 (by RAW) XXVII

[Gildedragon]

Q70

What's the best magic item for a single-use spell over 3rd level that is useable by all required classes? Basically, a scroll that doesn't require UMD.

A70 I think...
Best? You mean cheapest single-use spell delivery form?
The no UMD requirement limits us to wondrous items
single use-use activated ones (Spell level × caster level × 50 gp)
But as wondrous items are DM regulated...

Matters such as "Best" "Most Optimal" "Prettiest" etc are outside the purview of RAW

But actually the cheapest way to get a single use of a single spell without a UMD check is to get an NPC wizard to cast it (Spell level x caster level x 10gp)