We investigated how autonomous and controlled motives for saving money contribute longitudinally to self-regulatory coping, goal progress, and psychological need satisfaction/frustration. We also investigated whether mental contrasting with implementation intentions (MCII) facilitates saving through interactions with controlled goal motives. We randomly assigned participants (N = 364) to the MCII or control condition. We assessed self-reported motives, self-regulatory coping, saving goal progress, and need satisfaction/frustration over 6 months. Autonomous motives predicted greater task-based coping and, indirectly, goal progress and need satisfaction. Controlled motives predicted increased disengagement-based coping and decreased task-based coping, which indirectly predicted need frustration and reduced progress, respectively. MCII decreased the negative relations between controlled motives and task-based coping, and indirectly predicted saving progress. Autonomous motivation is associated with saving money and need satisfaction. Conversely, controlled motives predict the thwarting of psychological needs and decreased saving. MCII might improve self-regulatory coping and saving in individuals with controlled motives.