The issue mentioned by motleymermaid and CloezCorner is a bug that was introduced by our latest release that is causing an "Additional Item Cost" to show up in the shipping section of the preview, even when nothing is entered in that field on the lister page. Our technical team is aware of this issue and will have it corrected as soon as possible.
In the mean time, you are still welcome to go ahead and post these listings and they will post correctly according with what you entered in the lister page, regardless of what is displayed in the shipping section of the preview. The "Additional Item Cost" field only applies to multiple quantity listings, so it should be left blank for any single quantity listings you are posting.
Any additional questions or concerns? Please contact our customer support department using the appropriate link on our help page: http://www.auctiva.com/free-auction-software-help/help.aspx