Data augmentation alleviates the problem of data scarcity when training language models (LMs) by generating new examples based on the existing data. A successful approach to generate new samples is to fine-tune a pretrained LM on the task-specific data and then sample from the label-conditioned LM. However, fine-tuning can be difficult when task-specific data is scarce. In this work, we explore whether large pretrained LMs can be used to generate new useful samples without fine-tuning. For a given class, we propose concatenating few examples and prompt them to GPT-3 to generate new examples. We evaluate this method for few-shot intent classification on CLINC150 and SNIPS and find that data generated by GPT-3 greatly improves the performance of the intent classifiers. Importantly, we find that, without any LM fine-tuning, the gains brought by data augmentation with GPT-3 are similar to those reported in prior work on LM-based data augmentation. Experiments with models of different sizes show that larger LMs generate higher quality samples that yield higher accuracy gains.