Ollama downloads open-source models like Llama 2 and Mistral and runs them on your own hardware—no API calls, no subscriptions, no data leaving your machine. The pitch is straightforward: you get inference without the per-token pricing or rate limits of cloud services. The catch is real: performance depends entirely on your CPU or GPU, and setup requires comfort with command-line tools and ~10GB of disk space per model. It's genuinely free, but you're trading convenience and speed for privacy and control.