It looks as though the volunteer-provided content is still available free:
https://billiongraves.com/bgplus-buy-nowFees are charged for higher quality images, more precise GPS, and non-volunteer content. However, that page has a link to register for the basic (free) plan - is that now compulsory?
I also found this on the home page: "We've partnered with great companies like FamilySearch, MyHeritage and Findmypast. Whatever you find on BillionGraves is copied onto our partner sites!" So does that include the things you'd have to pay to see at BG itself, or just the free/volunteer stuff?