There's a few pricy items in the new gobbie bags (Adaman Ingot most notably, which *became* extra pricy because of these quests - it'll probably slooooowly drop back down over time). They also include Angelstone and Deathstone, but both of those can be quested in past Sandy in WotG (once only each, but that's enough for your gobbie bags). Nothing that an inventory-bloated 75 can't manage, but there are definitely cheaper options for improving your storage capacity.
Current limits for storage are:
70 inventory
80 mog safe
80 furniture storage (home town only, but that's not a big problem if you're sensible and keep HP there)
80 mog locker