I try to avoid buying black market after spending 300k on one SSR enchant lol..
That said:
Honor: I will aim to get the rune stone (500), followed by SSR accessory (1000) and lastly Trinity Voucher (150)
Friendship: I personally aim for 2 x Trinity voucher (1200) and then will exchange for rare crafter's hammer (50) all the time. EXP potions are easily farmable through Angelica's training and bright gems not really needed unless you're in a hurry to boost a character's bond.
Equipment: Rare martial spirit to upgrade SR equipment to their max (300) and then SSR item depending on which equipment on my main team is lacking utility (lacking extra skill on items like +3% to healing, +3% to defense when attacked etc). I imagine this to change once all items are SR, when the focus apparently will switch more towards getting Epic martial spirits to upgrade SSR items.