https://www.microsoft.com/en-us/store/p/halo-5-guardians-classic-helmet-req-pack/bxlwv33zw3xd
It shows up here. I have 10 dollars to splurge but don’t have an Xbox One. So if I buy it from here, can I use the helmets on Halo 5 forge on PC?
Yep, anything you buy you would be able to use. I can’t recall if you can change your armour in Forge, but you can change it here on Waypoint via your Halo 5 service record. Look for the link that says “Customize Spartan”
Additionally, if you didnt know already, you can open your daily login packs on Waypoint as well. So if you save up those points by discarding the items you get, you can put those points towards Silver packs and hopefully unlock more armour.