I was browsing the zip cashback stores (guess had nothing better to do this evening) and found that zip has an increased cashback of $19 for boost store purchases till the end of this month. Earn $4 from the $15 starter pack. I have also found that the Cashback appears instantly as a reward for redemption.
To earn cashback, simply click on the boost mobile store via the zip app and make your purchase normally and pay using zip.
Note: Cashback does not apply for $2 sim or $10 starter pack purchases.
Edit: As highlighted by @TanedaR here - redemption of cashback can only be done in chunks of $20.
Hope this helps some of us.
As always,Enjoy!
Oh. Seems they fixed it. I remember someone said they bought $2 sim still get cashback even after they updated $2 and $10 sim are excluded.