
The cheapest GPU cloud marketplace for AI workloads
Vast.ai is a peer-to-peer GPU rental marketplace where individual hosts rent out their idle GPUs at deeply discounted rates. It's widely considered the cheapest way to access high-end NVIDIA GPUs (RTX 4090, A100, H100) for Stable Diffusion, ComfyUI, model training, and inference workloads. Renters bid on instances via on-demand or interruptible pricing, with full SSH/Docker access to ComfyUI and Automatic1111 templates.
Hosts compete on price, driving GPU costs down to a fraction of major clouds.
Choose stable on-demand pricing or bid for interruptible instances at up to 50% extra savings.
One-click Docker templates for Stable Diffusion WebUI, ComfyUI, Jupyter, and PyTorch.
RTX 3090, 4090, A100, H100, H200 and more, often available globally.
Granular billing with no minimum commitment.
Built-in performance scoring helps you compare hosts on real ML workloads, not just specs.
Full root access via SSH, web terminal, or Jupyter for custom ComfyUI nodes and extensions.
Hobbyists spin up an RTX 4090 for $0.20-0.35/hr to run heavy ComfyUI workflows without buying hardware.
Affordable A100/H100 access for fine-tuning Stable Diffusion checkpoints and LoRAs overnight.
Render thousands of SDXL or Flux images in a few hours at marketplace pricing.
Test inference performance across different GPU SKUs before committing to a production host.
Best for cost-obsessed power users running ComfyUI experiments, LoRA training, or batch generation who don't mind picking hosts and can tolerate the occasional preemption.
Choose Vast.ai when raw price-per-GPU-hour is the deciding factor — hobbyist ComfyUI, batch image generation, fault-tolerant fine-tuning, and benchmarking before committing to a production host.
Rent storage independently to keep models and outputs across instance restarts.

The end-to-end GPU cloud for AI workloads