How to ship an item (cheap)?

I'm a newbie at this but basically I'm 15 and I live in manhattan so getting a job is really impossible at this age. So I decided to buy these really cheap iPhone cases from amizon from $1-3 and then sell them from like $8-10. I already have a Paypal account that's linked up to my dads bank account and he said he'd pay me the money in hand for the amount Id get from selling stuff online.

So I'm just thinking to make maybe a $5-6 profit from sellin each case, but I'm new to shipping them. How do I ship them once I sell them on eBay/Amazon? Can I use the same box I GOT the case in and just change the address to MY buyer? I want to avoid buying another shipping box from the post office as that would cost even more money…

If it's like those cheap silicon iphone cases with plastic wrap, why don't you just use an envelope, or a large manila envelope.

Buying some bubble envelopes from an office supply store is best, because they are light weight and don't add much to the cost of postage. If you buy the phone cases in bulk, they will come in one box. You can't mail objects in letter envelopes

Your problem will be that your potential customers may know that they can get them cheaper on Amazon.

If you list them for sale on eBay or similar site, pack them and weigh them before you offer them for sale so you will know how much to charge for shipping. EBay makes that real easy and buying your postage from them is the best deal around.