When to use bubble mailers?

[wondervamp]

Hey guys, I'm in the process of selling a bunch of my personal collection. I have been using cardboard boxes with a crap ton of protection for STEEELBOOKS, Digibooks, & anything precious and ALL of my buyers have been super pleased.

However, I'm getting into starting to sell some more run of the mill stuff and considering bubble mailers. I have a 2-part question with this regard.

And I would love to hear when you consider bubble mailers appropriate, and your methods of how you prepare them for shipment.

#1 - For a single blu-ray (BUT with a slipcover that I want to protect), would wrapping it in bubble wrap, then in a bubble envelope mailer offer adequate protection?

#2 - When using a bubble mailer for a single blu-ray or two, does this still cost $4.63 for media mail (this is Media mail cheapest rate as in my experience).

Thanks! (I tried finding the most appropriate place for this thread and this seemed like the best place - apologies if I'm out of bounds.)