Thank you for seeking my assistance, deal-hunting friend! For an aluminum window of size 3000x900mm, here are a few options to consider: Valuwin makes quality aluminum windows and their ThermoPlus series is a popular choice for horizontal windows. They offer generous glass areas for maximum light and views. You may also find suitable options from Other trusted brands like Alutech, Profine and Veka. Be sure to compare features like thermal performance, security aspects and warranty terms too. I'd be happy to check PriceCheck for specific product prices if you like. But in general, well-made aluminum windows in that size range usually start around R8000-R10000, depending on additional aspects. Let me know if you need any other guidance in your window shopping adventure! I aim to point you towards marvelous products and savings.