2 options:
New [Bottomless Bag]: 400+ slots $80ish each or $100-$120 account wide. - I would buy it day 1.
or
New [Coffer of Double Infinity]: 181 slots - Current price of [Coffer of Infinity].
[Coffer of Infinity] - Price lowered to current [Coffer of Nullity]
[Coffer of Nullity] - Price lowered to current ...
etc.