Best way to ship a lightweight item that is fragile and trying to offer free S&

[irenesshoppe]

Hi all

I would really appreciate any advice a seasoned or just knowledgable about packaging and shipping as a seller, anyone here can offer for a specific item of which I have 50, they are  6"x5" sticker sheets vintage and I am stuck trying to figure out packing, possibly offering free S&H and mailing out via USPS in a way that won't take all my profit!

 My venture  has been on hold bc I just cannot believe how much it costs to ship something so lightweight. I understand that it needs to be packaged appropriately so the item is not damaged (thin like a piece of paper) and on eBay and other sites as well, one in particular, that would be perfect but after fees and shipping fees, I don't have a printer so I pay UPS to print  labels at $3.00 a label I am left with less than 50% of the sale!

Anyone with experience selling something similar in size? It's thin like a sheet of paper , yet cannot get damaged, so I was thinking an envelope with cardboard to stabilize or  rigid mailers?

Options so far:

-6x9 rigid  mailer

-6x9 padded envelope

-5x7 envelope with card and cutout cardboard to help

-Flattest, smallest box I can find

All via USPS as I think that is the least expensive and anyone know how much the best option would be, even a ballpark figure? I have looked at that site far too long!

How do I decrease the cost to the cheapest and still get a tracking number for the customer?

Looking for any insight, suggestions, advice, constructive criticism even, if you think I shouldn't offer free s&h and go another route I am open to any types of alternatives as well. Thank you!