Sellers can set an opening bid which is very low on their auctions, to encourage bidding.
However, they can pay for a Reserve Bid and if the bidding does not meet that Bid, the item goes unsold.
For example, I want to sell by Antique Kazoo which I paid $500 for twenty years ago. I am convinced it is worth much more today.
I set up an Reserve Bid of $500 and pay eBay for the privilege.
But the auction shows an opening bid of $9.99.
You bid, and because you know the market for Antique Kazoos, your bid is $100.
Even if no one else bids, you will not win because of the Reserve.
But if Weird Al Yankovic comes along and bids $500, he will win because he did bid the Reserve.
Unless of course you jump back in and bid $600, in which case you will win because you met the Reserve and bid higher than Weird Al.
To complicate matters, you will not actually pay $600, but about $520 , which is one 'increment" above the underbid.
Bid once, bid your maximum and usually bid late. You will never pay 'too much' with that process.
