This build is designed for a new Warframe player who just hit MR2, bought [Mesa Prime], and wants to jump straight into the action.

The idea is to keep Endo (only 27k) and Plat cost very low, require 0 forma, and use no Primed or Umbral mods, while still maintaining:
1) 145% strength threshold for 95% damage reduction from Shatter Shield
2) Max efficiency (175%)
3) As much duration as we can get for cheap, to make maintaining her 2 and 3 easier and less energy/s

Arcane Velocity is included at max rank because it's very cheap currently (around 50p)
Arcane Aegis is added at low rank for some survivability without spending a ton of plat
Arcane Aegis could be swapped for Arcane Grace if you prefer, since you likely wont be relying on shield gating that much at this stage in the game
Eventually you will put Arcane Energize (expensive) in the second slot anyway, so don't invest too much into ranking up Aegis/Grace

Aura can be swapped, but there aren't many valuable options in the Y polarity. If you want Corrosive Projection, you'd need to forma the Aura or drop Preparation (which does technically save you 20 plat or an exilus adapter). We don't rely on Growing Power for our 95% reduction on Shatter Shield, so you can still cast it without the proc. Once we do get a status proc, our strength will increase to 170%, further increasing the damage of our Regulators Prime.

The majority of the star chart is short missions, and Preparation is extremely valuable for those, but if you want to alter this build to a long-mission variant, you can use this build to increase duration by 22% and gain 30% knockdown resist by giving up the initial energy from Preparation. This variant will also cost HALF the Endo and a little less Platinum since you wont need to purchase Preparation or Transient Fortitude.

Please review my budget Regulators Prime build, designed to synergize with this build.