depends on what you sell and how many you ship, the shipping price mainly depend on the volume you give to the shipping company. I know people enjoying as high as 54% markdown on base price of UPS, its all game of numbers !
I stopped selling on eBay because too many scammers. They file item not as described, and even if you win the case on eBay and PayPal, they can still do chargeback.
I personally think Ebay and Paypal have literary gone out of their way to make the whole experience bad for sellers and it is not worth the bother they put you through.
Packing and shipping shouldn't be a concern.. even on low volume, ideally the buyer pays shipping.. depends a lot on price point/weight/size of the items you are selling of course. As mentioned above, your biggest issue might be fraud.. You can make a lot of money on Ebay, especially choosing the right products. Heck, even acting as a junk broker buying stuff local/classifieds/fleamarkets/auctions/liquidations... misc., household, collectables, etc.. and selling the the global audience for premium value can be a great income.. products like these will also be less attractive to scammers.
Yeah I really think that it depends on a lots of things, like what you are selling the price and so on, but most of the time you will not sell anything.
My only problems with eBay are the excessive fees and lack of reasonable support for sellers. I have three main product lines and do over 100K per year in business on eBay but the fees add up to nearly $20K per year. One thing you need to look at is eBay is a great place to build a customer base for your own website. When I ship my items to buyers, I include a 10% off coupon for purchases on my website. Most of my repeat customers now buy from me on my site which cuts eBay out of those fees.
This is a rather pessimistic view. My experience is nothing but good .... maybe except for the fees, but on the other hand, does it really matter if you are making money? ... you will attract what you focus on -> law of attraction. Hope it helps.
Packing and shipping is not much difficult. If you use proper technique you can make huge profit on ebay. Also try using cheap carrier like USPS.