push the boat out
• be lavish in one's spending or celebrations.
• "from fine wines to the delights of the theatre, this is your chance to push the boat out"
Similar:
be extravagant,
go on a spending spree,
splash out,
splurge,
spare no expense,
spend lavishly,
spend a lot of money,
lash out,
go mad,
go on a shopping binge,
indulge in some retail therapy,
