i know coin stores sometimes have ones that are like 3 by 1.5...but they dont zip/lock at the top, u have to fold them over and tape them...hope this helps! Keep it up and hh! [R.I.P. Rich Hartford]
Be careful with what kind of plastic you put coins in (at least, any that have value). PVC/Vinyl, for one, damages coins.
I use flips made of BoPET (AKA Mylar). The brand name is SAFlips. Mylar is archival safe for coins and pretty much any other material, is very clear and has lower gas permeability.