Be extremely cautious. Sellers offering "$9.99 Lifetime Postbox License Code" on auction sites are almost always selling:
Never trust a "license generator" website. These are 99.9% scams designed to infect your computer with ransomware or keyloggers. Postbox License Code
A: You keep using Postbox forever. You simply stop receiving feature updates. Security updates? Postbox typically includes security patches within the same major version (e.g., 7.0 → 7.5) for free. Be extremely cautious
A quick internet search reveals dozens of websites offering "Postbox License Code for free," "keygens," or "cracked patches." Here is why you should avoid them at all costs: Never trust a "license generator" website