"Qualifying service plans" for Boost-Up?
I am considering taking advantage of the Boost-Up offer to move from my Samsung J3 Emerge to an Apple iPhone XR. I see the "Boost-Up" paragraph says the installment contract will include a "qualifying service plan." My searches on this website have failed to turn up any additional details about "qualifying service plan" options. Without this info -- that will help me know exactly what expenses I am committing myself to and what I may be sacrificing in the bargain when changing from my present (Double Data) plan -- I cannot proceed any further with a Boost-Up..
Can someone direct me to the specific "qualifying service plans" that the Boost-Up paragraph refers to?