Follow my link here:
http://www.ebay.com/gds/Secret-PayP...ps-off-eBay-Mailing-/10000000007215096/g.html
If you want you can weigh the package, but 4 oz is probably more than enough. Under service type, choose "First Class Mail Parcel", under package size use "Package/Thick Envelope" and click "The packaging is
irregular or unusual".
It will print you a label with tracking for under $3 and you can just put it in your mailbox. I schedule a pickup for free using USPS.com, but it's probably not necessary.
For a sample set, I like to put them flat on a small piece of cereal box and saran wrap it all up before sliding in the envelope. I've used masking tape before and had it peel off the inlay afterwards.