This contingent valuation (CV) study investigates the potential of cost-influenced responses in open-ended (OE) and dichotomous choice (DC) formats. For both formats we cross split-sample information treatments to provide: a total cost of the project treatment, a group-size treatment, a combined treatment, and the baseline control group. Investigations are undertaken using a CV survey for a particular environmental good (the ''field''), and in an induced value experimental laboratory setting with real payoffs and a context-free, publicly provided good (the ''lab''). Results show that DC values arenotaffected by cost and/or group-size information while the OE values are (negatively) affected.