Frontier model providers (Anthropic et al.) gate new accounts to impractically low rate limits and spending caps until clients unlock higher limits with cumulative usage, make equivalent cash deposits up front, or talk to a Sales department to work out some other arrangement. They are handicapped by the postpaid billing model.

It's an administrative burden to sign up very every model provider, and there are many independent inference providers now that serve only open source models.

OpenRouter provides a useful service by allowing easy prepaid model access with much higher rate limits, and they also aggregate different model providers to route queries by price, latency, etc.