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Free AI Tools
Engineering as marketing. Every tool is free, open-source, no login required. Like what you see? Scroll down to hire me.
FREEHOT
AI API Price Calculator
Compare OpenAI, Claude, Gemini, DeepSeek pricing side-by-side. Calculate your monthly cost by token usage.
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AI Wrong-Answer Book Generator
Snap a few worksheet photos. AI groups mistakes by topic, generates targeted practice, exports a printable PDF.
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China-US Tariff Calculator
Enter a price, instantly see tariff cost across 16 categories. Covers electronics, fashion, cosmetics, cars and more.
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Chinese AI Model Pricing Comparison
Doubao/DeepSeek/Kimi/Qwen/GLM/Hunyuan — API pricing + subscription plans compared side by side.
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More tools shipping soon
需要定制项目？我也接单 / Need custom work? I freelance too.
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