Truecaller Premium pricing varies wildly by region. In the US, Premium is ~$10/month. In India, it is ~₹150/month ($1.80). In Egypt, it is even cheaper.
Let’s assume you find a version that bypasses the server checks. The cost is significantly higher than a $5 monthly subscription. Here is what you are actually installing.
Many Platinmods mods request "Google Services" permissions. This allows the mod to steal your Google OAuth token. With that token, a hacker can log into your Gmail, Google Drive, and YouTube without ever needing your password. They can then reset your Instagram, Twitter, and WhatsApp.