My answer would depend on who you are selling your products to and how you are selling them.
If you are selling wholesale it would be best to offer free shipping with orders over a certain amount. I am unsure what type of jewelry you are selling, so you need to figure out that amount based on the goods you supply. If you are selling wholesale Sterling Silver and Semi-Precious stones I suggest a minimum order of $300 for free shipping .
All free shipping should be the most inexpensive shipping cost possible. If they would like faster shipping then charge them for the extra cost of the shipping.
If you are selling to individuals from a web based store it should not matter. They consider the entire cost of obtaining an item the cost of the jewelry piece they buy.
If you are selling at auction the shipping cost should be separate. The lower the starting price is on an auctioned item the more bids you will receive. Many people will get into bidding wars over an item and they lose site of the cost and see the purchase more as a win.
If you ship internationally and if you sell items at auction you can choose which countries can bid on your items (e-bay). You will need to set your shipping cost before placing your item up for auctions, so make sure you estimate high on shipping cost.
I have seen jewelry auctioned off on E-Bay for very low prices, but the shipping cost are outrageous . That is a very poor business move, because you want repeat buyers. I believe that E-Bay has put a stop to this practice now, but you will need to check to be certain.
