Have you ever noticed that when individuals do something a few times they act as if they are automatic experts in the area? Let's take for example a person that has sold on eBay. They may have sold 1-10 items and now they know it all. From the posting to final shipping they are now an expert.
If the items that they wanted to sell did not, boy do they have a lot to tell on why it did not sell and what to do to make it sell. Not all the advice is that that great as they do not understand the total workings of selling an item. Nobody really does as the public demands for various items changes with the weather. What is hot today is cold tomorrow. Yet these experts demand that they know all.
One of the first things that I hear is that they charged over the amount of shipping. This is one of the many reasons that now sellers have a ceiling on the shipping amount in media mail. Making no difference if it ships for over the maximum amount we are only required to ship at one flat cost. So I personally want to thank those that are not regular sellers for continuing the practice as it helps to screw those that do not over quote shipping prices. If you want $5 then start your item at that and adjust your shipping cost to reflect something reasonable. Stop trying to make money off shipping.
The next advise that they offer is how to sell the item. Auction or Buy It Now. Both are good ways to sell your item but each has its pit falls as well. A Buy It Now does not insure that your item will in fact sell at all. There are many items that you would fair better at listing at an auction price and adjusting your price at the same time. It may in fact save you on listing fees as well. Research your item first. Spend the time to look it up and use other sellers prices to sell your item. Yes, it takes time to do this but it might help you sell the item and not sit there for days on end only to not sell and you are paying the fee no matter what.
Complaining about questions asked to you. That is part of the auction selling. People do not always understand the way that a posting was written. Maybe it is unclear to them what you are trying to say. What is clear to you makes someone else dizzy. Yes, there are questions that you will answer that you just do not understand why they are asking. Such as in your listing you stated you combine shipping, only to be asked Do you combine shipping? Many people only skim the posting. A question, no matter how stupid to you is a potential sale.
Yes, there is money to be made on eBay. Obviously there is otherwise I would not have had a store front for a few years on eBay but there is work in it. Watching the trends, your costs, buyers reactions and of course w careful watch on shipping. Customer relations is top on my list as well as I have many, many returning customers. It is not as easy nor as hard as people say it is. It is up to the individual to decide how they are going to sell. The more you sell the higher your profit margin is.
For those that have sold a handful of items and now proclaim that they know all, you really do not. All you are is a sometime seller that wishes to make a quick dollar, which is great. But do not go around spouting off information that may not be good for another seller that is new.