Whilst still farily new to selling I have adopted the policy of "Free Shipping" on all my items unless they are substantially large/heavy items that the postage will differ between different locations.

I know what the postage is likely to be including any tracking SOD etc plus any overheads including any eBay fees and PayPal fees plus a few dollars minium for me depending on the items real value (which is usually a moot point as I am selling it because I do not need it). Then that forms the basis of my listing start price (not the stupid 99cent recomended by eBay). Some times I have a win with postage some times I dont. A couple of times I have just broken even but what the heck at least someone is getting a good deal. In the long term I am only interested in finding new homes for the many generations of accumulated clutter that I have acquried (I do not actively go out to buy anything for resale on eBay).

If the Australia Post Calculator charges too much (which sometimes is does) and the difference is more than a couple of dollars I will refund (this has happend twice and I have refunded about $10 each time). There are other times that I have a win when I allow for a 5 kg prepaid bag and manage to fit in a under 3Kg prepaid, if I have advertised as "Free Shipping" then that is my win and the buyer is none the wiser ( and still happy with positive FB)

Same as with low value items, I often look up the buyer address on Google maps and look at the demographics and make a judgement call as to likely "non delivery claim". If it looks like a block of flats with little security in a urban jungle I will SOD, If it looks like a genuine middle class home in a nice suburb I take the risk with a low value item and just send with no tracking or SOD.

Same as if delivered to a PO Box. I usually take the risk of no tracking or SOD.

So far I have been 100% accurate in my "assumptions" but I am sure one day I will wear a "non delivery".

Just the way I do business but I am sure if I was doing this for a living I would probably adopt a more agressive approach.