I've always posted giving a fair price that does not included the shipping or insurance. I always state i will not ship with out proper declaration of price or adequate insurance at buyers expense. I do this to cover both our asses if something happens during shipping. I also do not include any of the above in the price so to not inflate the price for a local buyer who may wish to pick it up. I always use Canada Post - US postal service at the express package level. I do this because like some one said above it requires an adult signature at the delivery point and it usually goes through customs easier-fast. I also have had better luck with the national postal services then the UPS- FedEx's but your mileage may vary here. I also always give the buyer my full name and address for return if something is amiss. Any deviation from this and I state its at the buyers risk for loss or damage (like i'm not going to get fussy on a $20 item but over $100 and i'm wanting insurance). Like others have said its not a done deal until the buyer has the item and is happy its arrived as the state it was agreed on. Always take the return unless agreed prior to the sale. Oh i don't accept PayPal as a form of payment as well i'm not comfortable with another institution having access to my banking. One last thing I never sell unless I have spoken to the buyer by phone as well as email much less issues that way.
I'm honest with condition when I sell and over pack every item. I think most of us are hobbyist and really like to share our hobby and discus our hobby I've met some wonderful audiophiles during the buying-selling process. These are the ones I prefer to sell to people like myself who love the music and hobby not the resellers and people looking to make a buck. If your honest from the start then if shipping issues do arise its easier to come to a solution that satisfies both parties.
Note i have used my local UPS store for packing and I find they pack very well here so not all UPS stores are below standard. And bubble wrap is your friend if done right.