For my build, 650W would be more than enough (1660 Ti + R5 2600x) but the offer is also very good. It's a relatively new brand called Mercury. The offer is basically an 850W Gold Fully Modular PSU from Mercury for the price of a 650W Gold Semi-Modular PSU. The offer might seem too suspicious, which it kinda is, but the retailer (He's really trustworthy and knowledgable about hardware and I'm going to buy the whole build from him) told me that it's a relatively new brand in the market, based in the EU, and has good sales here in Egypt and that he never got any complaints from it. It seems like a really good deal to me especially since it's Gold-rated, so the efficiency of its parts and power consumption should also be very good. What do you guys think I should do in this situation?