I’m having a hard time finding an affordable peel and stick (vapor barrier) that is not modified bitumen. About the only one I found is Grace Ultra that is reasonably priced. Any budget friendly alternatives out there?

I’m trying to avoid rubberized asphalt adhesive as there will be an EPDM roof over it. Just need something that will hold up for a couple of months of UV exposure till the exterior insulation and membrane is installed.