Secondhand retail in the UK charity sector plays a number of important social and economic roles: charity shops are community focal points; money is generated for good causes; and goods are re-circulated that might otherwise be discarded as abject and unwanted. However, like much of the UK high street, the prosperity of charity shops is under significant threat from the rise of internet shopping. Access to online markets via smart phones equips customers to check prices for secondhand items, some customers then deploy information, usually from eBay, to haggle with shop staff. This demo presents the Haggle-o-Tron as a design intervention into an Oxfam secondhand shop that playfully subverts bo th normative and emerging secondhand retail valuatio n practices by revealing secondhand goods’ financial, moral, social and aesthetic properties. This demonstration proposal is for a demonstration that will present both the design solution and documentation of its role within the ethnographic study.