Some questions about eBay?

[Akami Kitsune]

So I know that most of these will seem stupid but I'm new and I want to know what I get myself into.

Firstly when should I pay? Before or after I get the item? Also what if I don't get the item but payed? What will happen then?

Secondly what does Free Shipping mean ( I mean is it really free or is just cheaper because let's say that I want to buy something that cost 6.00$ and it's with free shipping, but how would this be advantageous for the seller, shipping to my country is 17.00$ so wouldn't the seller just lose money?)

For example (the first item from here)
http://www.ebay.com/sch/i.html?_odkw=Dan...&_from=R40

- it says that is free shipping but when I click it:

http://www.ebay.com/itm/Non-Slip-Dance-R...3a7a3a72c0

it says:
Shipping:
FREE Standard Int'l Shipping | See details
International items may be subject to customs processing and additional charges.

Item location:
hong kong, Hong Kong

Ships to:
Worldwide


So it is free shipping or is it the Standard Int'l Shipping thingy? BTW what does that mean.


Thanks for the help!
Sorry I'm not sure I put the question in the right category...
Also what if I'm not home when the item is delivered? Where does it go? How do I know when it comes? What if it comes later?