Instead of risking your business with a crack, consider these options. They are legal, secure, and offer "forever free" tiers for small businesses:
Offers a very robust free version for small shops that includes sales control, stock management, and customer registration.
A 100% free ERP and POS system that includes inventory control and tax invoicing. They make money through partnerships, not by charging the user.
A great free app for tablets and phones, perfect for cafes or small retail shops looking to manage stock and sales easily.
If you are tech-savvy, Odoo is a world-class open-source ERP. The "One App Free" plan is excellent if you just need inventory or sales.