The most likely reason for this is that the vendor charges a small amount for shipping. As amounts less than 0.00 don't show up in prices displayed in the shopping cart, it is highly likely that the vendor in question is charging 0.009 or thereabouts for shipping, or else the combination of what he is charging for shipping and the item itself (not 0.14, but 0.14542438 etc.) is bringing the total up to 0.15. Silk Road has no need to implement an "invisible sales tax", and DPR is entirely upfront about ALL fees. Libertas