Hi LitPrints,
I mainly work with 1" buttons and 2.25" compacts, but after some trial and error I figured that wrapping them in bubble wrap is best... I actually had a couple of customers about 10 years ago, that sent me back the envelope, the button had actually come out of the bottom of the envelope...another instance the button was dented! So, you really don't need a bubble mailer, it's actually cheaper just to buy a roll of bubble wrap and wrap each order...
Hope that helps,
Grue