Silly Money Meaning

(idiomatic) A ridiculously large (or, less commonly, small) sum of money.

Example:   Buying a house in central London will set you back close to a million quid, these days – it's just silly money.
1996: Mike Lawrence, A-Z of Sports Cars
  With collectors prepared to pay silly money for limited edition cars, Aston Martin commissioned Zagato to build a new body on the Vantage chassis.
1999: Jon Broome, The NEC Engineering and Contruction Contract: A User's Guide
  Representatives of both the Employers and Contractors thought that the potential to make ‘silly money' was not within the ECC.
2005: David Belbin, The EBay Book
  12p is a small price to pay to save on inconvenience and get a shot at someone paying silly money for your item.
2005: Benjamin Craig, Cannes - A Festival Virgin's Guide: Attending the Cannes Film Festival for filmmakers and film industry professionals
  Standard prices range from about 180€ - 500€ per night (unless you're looking to spend really silly money).