MTX Sales

Hi guys, I'm new in the game, started in Delve.
I bought the Soulstealer pack, because I liked it and I would want to buy something neutral, gray or dark like Sin's armour, (so I don't have trouble to combine it with the colours of the skills since I don't own too much money)
Should I wait for a Sin's or something similar for sale or it mostly won't happen in months?
Thanks for reading and sorry, english isn't my first lenguaje :)

You can wait, a Sin/Innocence sale shows up every month.