Color spray cost me 50 to scribe.

Melfs on the other hand cost me 450, which seems quite pricey.

Bug? I haven't tested the other spells.

The spells vary, protection from alignment costs 50 while the spell shield costs much more.

This is the default Bioware pricing. We haven't yet changed it.

We do plan on customizing crafting skills such as scroll scribing, potion brewing, and wand making, so that they have reasonable pricing schemes -- but we have not done so yet.