Whatever one you get, make sure it has an adapter to plug in, because it will shut off on you in the middle of weighing something, and that is a pain. You can buy one that won't do that. Just read through the description very closely.
Bitter Creek North has these. http://secure.candlesupply.com/catalog_page_detail.cfm?queries_index=index7&title_bar=Kraft%20Brown%20Soap%20Boxes&recordno=11&Product_CatalogID=2819&ProductNumber=pKrftBox&ProductCodeID=48&ProductSubCodeID=89&NewProduct=0