All you can do is perform a completed item search for the item you wish to list and then base your opening price on previous successful listings. You also have to take into account your low level of feedback and inexperience as a seller, most buyers will not bid as high on your listing as they would with an established seller.

Don't start it at a very low price unless you are prepared to let it go for that much.

Another big factor will be postage cost, make sure you quote an accurate amount for properly tracked postage so you are covered if the buyer says they have not received the item.