Vast.ai

One of the best places to rent a GPU by the hour. Vast is a marketplace: hundreds of independent hosts and 40+ datacenters across 60+ countries list their cards, the market sets the price, and it often comes out several times cheaper than the big clouds. 68+ GPU models from an RTX 3060 to a B200, and on verified hosts a 3090 goes from about $0.12/hr, a 5090 from $0.41 and an H100 from $2.6. Per-second billing, and interruptible instances are 50%+ cheaper if you are fine with being paused. Ready templates for PyTorch, ComfyUI, Ollama and vLLM get a local LLM, an AI agent or a GPU node for a testnet running in minutes. Pay by card or crypto. Two things to keep in mind: storage keeps billing while an instance is stopped, and hosts vary a lot, so for anything serious pick verified ones with high reliability.