PromptBase is a marketplace for buying and selling quality prompts that produce the best results, and save you money on API costs.

The platform lets “prompt engineers” sell text descriptions that reliably produce a certain art style or subject on a specific AI platform. When you buy the prompt, you get a string of words that you paste into GPT-3, Midjourney, DALL-E, or another system that you’ve got access to.

Source: https://www.theverge.com/2022/9/2/23326868/dalle-midjourney-ai-promptbase-prompt-market-sales-artist-interview