I prefer it when a seller charges me actual shipping costs (or close to it). I hate it when I'm charged $10 for shipping, and when the package comes, the postage says $2
Offerring free shipping for a certain dollar amount could also be very successful. If I'm only buying items that total $40, but I notice that there's free shipping on orders of $50, then I will look for something else to buy that will give me the free shipping. BTW, I'm just checking out your site now! I might have to wait a couple weeks to place an order (I've been on a doggie shopping frenzy and it's starting to catch up to me
). Good luck with whatever you decide