StackBest AI APIs & LLM providers for solo founders
If your product calls an LLM, token spend is usually your most volatile cost line: it scales with usage, not with plan tiers, and one chatty feature can double your bill overnight. Every provider here is pay-per-token with no seats and no contracts, and each one ships a ladder of models from cheap workhorses to frontier flagships, so compare price ranges per provider rather than a single model. For judging model quality per use case, skip the marketing pages and check neutral leaderboards like LMArena (lmarena.ai) and Artificial Analysis, then match the cheapest model that clears your quality bar.
| Tool | Free tier | Paid from | Best for |
|---|---|---|---|
 OpenAI$0.20-$5 /1M input | $0.20-$5 /1M input | Founders who want the safest default with the most tutorials and a cheap nano tier for high-volume tasks | |
 Anthropic Claude$1-$10 /1M input | $1-$10 /1M input | Founders building coding tools or agents who will actually implement prompt caching | |
 Google Gemini$0.10-$4 /1M input | $0.10-$4 /1M input | Pre-revenue founders who want to validate an AI feature for literally $0 | |
 xAI$1-$4 /1M input | $1-$4 /1M input | Founders who want frontier-class output below Claude and OpenAI flagship prices and are fine with the data-sharing tradeoff for credits | |
 DeepSeek$0.14-$0.44 /1M input | $0.14-$0.44 /1M input | Cost-obsessed founders whose users will not object to a China-hosted model | |
 Moonshot AIroughly $0.95-$3 /1M input | roughly $0.95-$3 /1M input | Founders who want a frontier-class open-weight reasoning model and long-context workloads without surcharges | |
 Alibaba Cloud (Qwen)$0.10-$2.50 /1M input | $0.10-$2.50 /1M input | Founders who standardized on Qwen models and want first-party pricing with a self-host option later | |
 Mistral$0.15-$1.50 /1M input | $0.15-$1.50 /1M input | EU-based founders or anyone who wants a self-host escape hatch | |
| $0.05-$1 /1M input | Founders whose feature works on open models and who care about speed and cost above all | ||
 Together AI$0.17-$1.74 /1M input | $0.17-$1.74 /1M input | Founders who need many open models plus fine-tuning under one roof and expect to scale to dedicated capacity | |
 OpenRouterpass-through of each model's provider price across 400+ models | pass-through of each model's provider price across 400+ models | Founders still choosing a model, or apps that let users pick their own model |
Judge quality with neutral leaderboards, not vendor pages: check LMArena (lmarena.ai) and Artificial Analysis for your specific use case, then buy the cheapest model that clears the bar. Start on Gemini's free tier or Groq's no-card free tier to validate the feature for $0, then put your production default on a cheap workhorse: Gemini 2.5 Flash-Lite ($0.10/$0.40), Qwen3.5 Flash ($0.10/$0.40), gpt-5.4-nano ($0.20/$1.25), or DeepSeek v4-flash ($0.14/$0.28) per 1M tokens.
For coding or agent features, pay up for Claude Sonnet 5 at the $2/$10 intro price but budget for $3/$15 after August 2026, and consider Grok 4.5 at $2/$6 as the value flagship. Turn on prompt caching before you scale, it cuts repeated input to 10-25% on most providers.
A typical solo SaaS with a few thousand AI interactions a month lands at $5-30/mo on a cheap model or $30-150/mo on a frontier model. Use OpenRouter only while comparing; once you commit, go direct and skip its 5.5% credit fee.
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