Nothing but a browser for the main path. The Hugging Face Space we tested needed no account, no install, and no card. Every browser step in the main path ran this way.
A paid option exists if you want it: Black Forest Labs' API. BFL's price list shows 0.9 cents per image at the standard 1K size (about one megapixel), rising to 1.4 cents at 2K and 3.6 cents at 4K. Their playground needs a free account first.
Running the model on your own machine is possible too. It needs an NVIDIA graphics card with 8GB of memory or more, plus some technical setup. That lane is named below, not required.