Do they fill balloons with helium like ones you didnt buy there?

Yes they do

Yes most all safeways have a place to fill balloons close to the floral department

no

I'm pretty sure they will only fill balloons that have been purchased there. I think Dollar Tree is the same.

I don't know if they do that there but there is a dollar tree next to Joanne and Ross it's in the middle . I know for sure that they have it