in space time u can sell basic/medium refine runes + all the unwanted upgrade scrolls u got (except kage scroll i think idk why lol). each give a specific amount of bet chips which u c*e to bet on space time players if u want to increase the amount or just straight out redeem them for some other stuff (like small stamina potion, cultivation rune pack, random lvl 2 magatama pack...)

but ur idea's cool, kinda like it since i get lots of epic and advanced runes from events compared to medium ones. Gahhh that's where i stop T^T

anything that's not p2p is not really on their priority list. it's a great idea for f2p but they have no incentive to do implement it.