There are a few ways to have an auction. If the item is really valuable, they tend to have a "reserve". Meaning that even though you may start bidding at .99 cents, the product will not sell unless the reserve is met, which would be $4,000 or whatever.
Since I am selling average/name products not collectors items I may do this:
Item: Ludwig LM 402 14x6.5" supraphonic used/like new
You want no less than $300
Start bidding at the minimum price you could part with the item. Any lower, and it could sell and you are out.
Start bidding: $299
Set a "buy it now" price that is reasonable. $375.
Customers know what you have in mind, they might try to bid, or just decide $375 is fair and buy it with no hassle.
Both have worked for me. Either I get my minimum price, buy it now price, or sometimes they get in a bidding war and someone pays more than "buy it now."
Thusfar, I have only sold ONE item below what I wanted to. And that was years ago. It was one of those "live and learn" things.
Make sure you include the phrase "I expect immediate payment upon winning" otherwise some clown will use ebay like a lay away service and you won't see a dime for a couple weeks. If they play this game, DO NOT give them feedback. If you give these people anything less than positive feedback (no matter how bad they are) they use it as an excuse to leave a false negative for you. False negatives are very difficult to contest, unless they are blatantly obvious. Ebay sees in shades of grey, because they have gone overboard to protect idiots that do this. The other bad part is that paypal will not release your money until long after the item is shipped and received unless you get a positive feedback after it's shipped. Clowns could separate you and your money by up to 45 days.