Auction style - Means you list the item with a starting price for bidding, with the option to buy it now.
There are Buy It Now only auctions, with the option to Make an Offer. Usually these are people with an "ebay store" that allow for listings to stay up for 30 days. Most auctions only last 7 days.
Ebay fees for a $9.95 item with a $24.95 BIN option
Insertion Fee - 25 cents
BIN fee - 10 cents
Schedule fee - 10 cents (if you would like the item to start at a selected time other than when you are listing it).
Final Value Fee - a percentage based off your rating. Lower rating, higher fee. 7% is about as low as it gets.
PayPal fee - 2-3% when the person pays you.
Ebay generally offers a 100 listings free during the first week of the month. With the occasional offers in the middle of the month.
If you have a highly valued and sought after item, you can start your bidding at a lower price to reduce your fee. If it's a high valued item, but not highly sought after, then start your bid at the higher price, because people will not be in a bidding war at the end to drive the price up.
Example:
Listed a Zojirushi breadmaker, had 47 watchers at the end, and about 20 bids. Sold for 122$, starting bid 75$
Listed an Onkyo remote for a tv, had 3 watchers, and about five bids. Sold for 61$, starting bid 30$