I'm very new to selling on eBay and I would love to get some help. The objects I intend to sell are very small (ie phone cases and protectors) and thin. I heard that such objects may be shipped using an envelope and through letter delivery, hence being very cheap. Can someone tell me the  risks associated with such a delivery method as well as how to avoid these risks. 

One more thing, do CD mailers count as envelopes (and hence cheap shipping)? 

Also, i noticed these CD mailers http://www.ebay.com.au/itm/100-152x132x16mm-CD-DVD-DISC-MAILER-Mailing-Box-Rigid-Envelope-Large-Lett... for a pretty cheap price. Ik this question may seem stupid, but I'm extremely new to all this... Would these envelopes need stamps before being shipped out? If so, how many stamps will they require? How do I know which envelopes need stamps and which don't?

I really need help and would really really really appreciate it if someone could help me solve my problems. Thanks 🙂