As a buyer, you are naturally interested in purchasing the items you want for as little as possible. As a seller, you are interested in getting as much as possible for the items you are selling.
Here's how a sale normally goes:
At least, that's how it should go... and as a rule I find that nine times out of ten, everything goes according to plan.
When things go wrong, the problem is often one of expectation.
Read the small print
Most listings consist of two parts. The first part is the description of the item up for grabs. Part two is what I call the "small print", which establishes the ground rules and the seller's standards. This should give you an idea of what to expect with regards to payment options and expectations, delivery methods and timetable, return policy etc. Read and understand this stuff before you bid!
Too many buyers have gotten upset when the seller has done precisely what they said they would. For instance, if the seller states that they only go to the Post Office on Thursdays and they get your payment on Friday, don't go getting upset when it takes nearly two weeks for your merchandise to reach you.
I have a rule that I follow when reading a listing. I call it the "two-minute test". If I cannot read and understand the listing within two minutes, I tend to bail out and move on. By definition this tends to rule out the megasellers, with their exhaustive rules and paragraphs of small print.
Check out the seller
When it comes to checking out the seller your most useful ally is. Feedback. These are the questions that you should ask...
The number of feedbacks is a good indicator - though not an infallible one - of how reliable your seller is likely to be.
Personally I tend to look for sellers with two-or-three-digit feedbacks; more than 10 but less than 1000.
A word about dealing with Newbies. Conventional wisdom says that dealing with newbies is a risk. Often they do not understand how eBay works, which can lead to bad blood and ill-feeling. Sometimes they think that their listing is an "option to sell" and do not understand that a listing is effectively an offer for contract. This leads to an unpleasant surprise at the end of the auction, when they realize that and at the end of the auction they are obligated to sell the item at the winning bid.
Having said all that, some of my best eBay purchases have been from newbies. Sometimes they make mistakes in presenting their items that works in your favor.
Just remember to check them out thoroughly before bidding!
If your seller has 50+ feedback, the following is a useful rule of thumb. Below 50 the numbers get skewed too easily to be useful.
One of the biggest annoyances about eBay feedbacks is that there is no easy way to check all of the negative and neutral feedbacks. I suspect that this is deliberate; perhaps eBay are trying to downplay the negative aspect of the system. You used to be able to search the sheets for the words "Neutral" and "Complaint", but then eBay redesigned their pages and removed that feature, so now you have to pore through pages and pages of feedback comments in search of the occasional negative... or do you? There is an external web site - toolhaus.org - that can search all non-positive feedbacks for a member, among many other useful features.
The art of asking questions
When it comes to eBay listings, never assume anything. If you are not sure about something or have a question that is not covered in the listing, use the "ask a question" link. Sometimes the seller forgot to put in an important detail or simply made a mistake. If the shipping cost is stupidly high, ask for confirmation - hey, they're human too...
Don't be afraid to negotiate
Just because the seller has taken the time and trouble to put together a listing does not necessarily mean that all conditions are set in stone. Sometimes the seller will negotiate, particularly on shipping, which is often an educated guess. Note that this is not the same as asking the seller to "go outside eBay", which is against eBay's terms.