Ending today, Boost Mobile takes an extra 15% off a selection of Android phones via coupon code "SHIP2018". Plus, the same coupon bags free next-day shipping on all orders. A couple of best bets, with prices after coupon:
LG Tribute Dynasty 16GB Android Phone for Boost for $42.49 (pictured, low by $48)
Samsung J7 Refine 32GB Android Phone for Boost for $127.49 (low by $22)
With these companies, it might be easier than you think to negotiate your monthly bill down.