One featured 5-star cycle needs 90 pulls (14,400 Stellar Jade) if you win the 50/50, and 180 pulls (28,800 Jade) guaranteed worst-case. That's about $200 at average luck (16,160 shards) and $315 safe budget (25,330 shards).
Best value Blood Strike Golds top up bundles isn't biggest = best. It's math + bonuses + your goal. Single draws cost 90-150 Golds, 100-draw pity = 9,000-15,000 Golds (~12,000 average). First-purchase doubling makes small packs win on fresh accounts, while 5000+800 wins after bonuses. And the refundable 520-Golds Elite Strike Pass is your low-spend anchor.