http://pages.ebay.com/help/sell/fees.html#auction
And the free listings will still charge you for PicturePak (6 to12 photos in you auction), Buy It Now, Reserve price, etc. so you have to be careful what options you pick to keep the listing price down. Then, as someone said, there's always a final value fee at the end based on the final price it was sold for. You can take the one free pic eBay offers, load all others to a public Photobucket album, and put a link to that in the auction.
Also, if you are a noob to eBay, you'll have to take PayPal for payments, and eBay and PayPal will hold hour money until either the buyer posts positive feedback or for 30 days. Upload the tracking number to eBay and PayPal to speed up the process. But you'd still have to front the money yourself to ship the item. Maybe just get a more experienced friend that has over 100 feedbacks to sell it for you.
Whenever you take a PayPal payment, keep all shipping and insurance receipts and print out the proof of delivery and retain all of that for 6 months. Scammers try to get items then claim they didn't and do a credit card chargeback via PayPal. And credit card companies will let them do that 3 months later.
Always ship it insured and use Signature Confirmation for USPS or signature required for UPS or FedEx. Insurance is for YOUR protection, not the buyer. If the item arrives damaged or it goes missing, and you don't have insurance, you are still considered self-insured and you will have to reimburse the buyer. Never insure for more than the purchase price b/c the carriers won't pay you more than that.
Keep the box size small as possible. Pad the saddle. Take the leathers & irons off it, coil the leathers, and wrap the L&I separately in bubble wrap or newspaper so they can't gouge up the saddle. Pack the saddle yourself b/c those shipping places won't do it for free and will charge you a hefty fee. I wrote some packaging instructions at Horse Grooming Forum.
For ebay use calculated shipping and put in a handling fee that covers the cost of the box, tape, signature fee, and insurance. $10 - $12 should do it. The calculated shipping doesn't cover that. so you have to add it as handling if you don't want to pay it yourself, and who does?