have you looked into the secondary market by chance? I've seen a lot of good deals on both parts and fully built rigs lately. I've went as far as purchasing a few parts in Reddit and from Ebay and they were cheaper than going to a store like Frys for example and you're helping someone else that probably needs a little cash!
I definitely recommend if you do go the secondary market approach you make sure wherever you buy has a review system for sellers or I've even heard of the sellers willing to do a background check on one of those background sites like www.backgroundcheckrepair.org/ just to be safe and more than anything just to see if the seller is cool with you seeing who they are. I feel like you can never be too careful buying online nowadays but it can also be because I've been taken advantage of in the past.
Anyway, although I know for sure the Logitech G510 Keyboard is amazing it's also pretty dang expensive. I've seen some others recommend some good alternatives that are a couple hundred lower in price. As you know, when building your own rig the less you spend on keyboards and that type of thing more you can spend on the graphics card and other important things that will help with immersion in the game. I've heard great things about the Nvidia GeForce RTX 3070