As a buyer you receive protection from Paypal for items that aren't shipped to you and for items that are significantly different from what was described.  The protection you receive is described generally here, and in greater detail here.  You also receive protection from eBay.

If you are planning on selling an item, and you want to be able to accept credit cards as payment, you will need to establish a paypal account, which can do by clicking here.  At the top of the screen, choose "Sell On eBay."  Then choose "Paypal for eBay sellers." 

You can order boxes for shipping your eBay items via the U.S. postal service, by going to this website.  Choose one of the two boxes labeled "Flat Rate Priority Mail."  Anything that can be fit in either box, can be shipped anywhere in the United States for $8.95. 

You can also pay for postage online, and print out postage using your home printer.   You must sign up for this service, which is offered by the U.S. Post Office.  Once you sign up, you can then print postage at this website.

If you'd like to sell an item on eBay, but you don't want to list it yourself, you can take your item to any UPS store and drop it off there.  UPS will list the item for you on eBay and ship the item as well.  This service is described in detail here.  Another company that offers eBay services similar to UPS is www.i-soldit.com. They have an office in the Shops at Potomac Valley which is located at 12101 Darnestown Rd.  Gaithersburg, Md 20878.  301-990-2040