Income targeting in industries where workers are free to set their hours is an economically important example of reference-dependent preferences in a naturally occurring setting. We design a set of field experiments in a market in which we link expected and unexpected transitory changes in wages to labor supplied amongst vendors who are free to set their hours. Consistent with neoclassical theory and reference-dependent preferences with endogenous reference points (Koszegi and Rabin (2006)), vendors supply more hours when presented with an expected transitory increase in hourly wages. However, in contrast with the prediction’s of behavioral models, when vendors earn an unexpected windfall early in the day, they do not respond with any change in their hours worked. The data also speaks to the possibility of reference-dependent preferences over other dimensions. The market we study is characterized by vendors that do not post prices but rather bargain prices with customers and our findings support neoclassical theory, as negotiation patterns are not affected by the unexpected windfall.