Quote from Sunureu13;341281:
Sprout isn't that expensive. On Tarlach they're 100k or less. A lot of times you can find them at 50k.
In Ruairi they're 30-70k as well, averaging at 50k. Not rare by any means... I casually put together my sprout trinity set lol But yeah since you state you only need prefix for clothes Fickle is about your only choice. Stage would be the step enchant used prior. Fickle is r4, stage is r5 enabled.
Fickle is obtainable from: Enchant Scroll (Barri Adv for Two Reward)
Stage is obtainable from: Enchant Scroll (Barri Adv Reward, Ifrit)
So barri advanced is going to be your new best friend... however since they're r5-4 and you seem to want to put it on your karis which may be pricy, you should use enchant protection pots.
Fickle Enchant Stats: MP+10
Int+10
When using the Diligent title, Balance+10%
When using the Lazy title, Critical+10%
Hope this helps ^.^
edit: Also I just thought I'd throw this out there (I don't know how plausible this is or whether it applies to you) but if you're not using a spirit weapon wand, and have a staff or wand you use most you could consider "Mana Conjurer" for your magic weapon. It's a prefix, rank 7 -.- But rank-enabled (doesn't need steps).
Mana Conjurer adds:
If Thunder Rank 9+, MP Cost Reduction+2~4
If Ice Spear Rank 8+, Magic Attack+2
Will+10
Personalize
And can be found in: Exclusive Enchant Scroll (Enemy Behind - Elite)
If you did come across one and used it, it might open a slot or two in your magic set