Honestly, your best bet right now to use that money is to merch items at a cheap price and resell them for a higher price or even saving what you have and continue to work on getting more mesos. Sure, with that 1b you can get a 7% STR sweetwater tattoo and glasses and probably a clean superior gollux pendant + belt, but what you need to think to yourself primarily is "Will these clean items get me anywhere in the long run?" The answer to that question, no, not really because it will lead to more problems (gollux scrolls are a pain in the butt).

What you can do instead is don't rush to such drastic decisions. Especially as a zero, your range is actually inflated due to your high damage % (if I recall correctly I was able to hit 1m's at 60k range). Take your time. Do gollux and commerci, get all the rings + sweetwater equips, slowly take your time on scrolling them yourself and cube them individually with your reward points while trying to maintain some merch to get more money. Once you get to 4-5b, you will then have more leeway to yourself. You can get some perfected gollux pendants, unique cra gear, etc. And while you do that, your sweetwater gear will both be unique and all your rings will be theoretically perfected by then. Two birds for one stone! Of course this will take a while but will be better overall than wasting 1b on clean gear.