A key strategy to motivate proenvironmental behavior (PEB) involves the promise of monetary rewards. Financial incentives are intuitively appealing because they can increase an individual's expected benefits for engaging in the PEB; however, there is concern that incentives can transform motivations for the PEB. The purpose of this study was to examine the role of financial incentives on behavior across time. Specifically, I used an experimental design to examine the immediate effects payments on litter-removal effort (Phase 1) followed by effort after payments were no longer available (Phase 2). Undergraduate students were recruited for a trail evaluation study and randomly assigned to a control treatment or a financial incentive treatment. In Phase 1 I asked students to pick up discarded litter during their trail evaluation (PEB). The incentive condition offered students $0.25 for each of the possible 16 items of trash planted along the trail. The control condition simply asked students to help by picking up trash. Students were again asked to collect trash in Phase 2 but the financial incentive condition was not offered a payment. In accordance with self-determination theory I expected payments to increase effort in the short term and suppress effort when the incentive was no longer provided. Although there was an overall decrease in effort between phases within both conditions, the results of a repeated-measures ANOVA indicated no difference between the control and incentive condition in either phase. Given the lack of a statistically significant finding, it is possible that there are conditions under which payments provide no greater inducement than a simple request for help. This idea is supported by a meta-analysis, which identifies a consistent lack of effect for easily-performed tasks. Additional research is needed to further understand the conditions under which financial incentives can motivate and sustain PEBs.