Finnish startup Metroc is using prisoners to train its AI model for less than $2 an hour. The AI model is used to provide construction companies with information on projects that are hiring. The company's business model is based on cost savings from deploying an AI model and using low-cost services of Finnish prisoners. Microsoft-backed OpenAI also uses cheap labor to train large language models. The practice could widen wealth inequalities, according to a McKinsey study.