Castings of lower level spells (namely cure wounds and remove curse) can be purchased from casters of appropriate levels which may be found in sufficiently large towns and cities for the cost of 100gp/spell level.
Realistically, spell casting should have a logarithmic/exponential cost instead of a flat per-level cost that reflects the additional time/effort required to reach those levels. Of course for magic users when possible I use the rules that magic users primarily level up via research & arcane work (including spells) so cantrips and level 1 spells will usually be cast at not much "above cost" given the caster is probably working to perfect their craft and welcomes the practice. Once you hit lvl 2 spells, now the casters are wanting real wages.
You stat to get to lvl 4 spells and the Wizard is probably going to want favors as well as gold.
Granted I will usually brew up a non-playable "Priest" class (cleric with the combat abilities stripped out) to occupy the local chuches and temples, which will pray for the party using over priced incense and gems, but in those cases the treatment only has a chance of working fully - they can try another round of crystal healing to cleanse their auras, but they gotta pay.
Maybe a fun way to go about cursed items is to allow them to "flip" similar to how a cursed scarab of protection would turn into double strength scarab?
I like the immortal lich king example too. If you make it a quest to cleanse a very powerful cursed item you get a very ring to mordor campaign where someone has to bear the weight as you travel, but if that person also knows the item they carry will be reversed in the end it might make it sting less.
I would probably have some % chance that decursing a bag of devouring turns it into a bag of holding.
If nothing else, maybe have it so perhaps some of the reagents used in the items' creation might be recoverable.
I have nothing for cursed scrolls though, especially considering how high the odds are you roll one on the random table for scrolls. I am pretty sure that is a way to lose a player, especially if you drop one in kind of early on where the MU likely already isn't doing a whole lot per session. Just feels like a complete douchebag move as a GM.
My recommendation for scrolls is this:
I would not have cursed scrolls in random loot tables (some exceptions; you are in the Tomb of Tommy the Cursed Scroll Scribe, I am going only going to laugh when someone picks up a scroll off the ground and gets easily foreseen consequences. Or maybe exceeeeeeeeeeeedingly rare). any cursed scroll be will planned and planted.
Teach the party very early on that not all scrolls are good. The worst ones should be hidden in scroll holders that very clearly give away "Maybe not read this one". Unknown scrolls should be used in desperation and really should be regarded as loot to take back and maybe sell.
Basically: There should be some way to determine roughly what a scroll is without reading/using it. Healing spells must be on vellum. Divination scrolls must be on papyrus. Conjuration spells must use gold ink. shit like that.
Then figure that your Legendary Figures, your once-a century geniuses, figured out a way to get around that and disguise scrolls. You can turn discovering these ruses in to a dice-roll test of abilities and/or luck. But usually when these things happen I like to make it clear to players:
You got fucked by a guy deliberately trying to fuck you. You couldn't have known before hand, just take the learning experience.
And of course, the result for a good player is that same trick won't work a second time. (unless its literally a straigth probability mechanic, but I try to avoid those)
