Police are trying to trace the owner of 65,400 euros (£44,000) mistakenly sent to a 16-year-old boy who bought a Playstation Two for £95 on eBay.
The cash arrived in a box at the house in Aylsham, Norfolk, with the games console, but minus two games.
Police are holding the money under the Proceeds of Crime Act while the matter is investigated.
An eBay spokesman said the parcel's contents were "somewhat unusual" and it would help police with their inquiries.
The boy's parents, who are not commenting, alerted police when the parcel arrived on 20 March.
Magistrates have given Norfolk Police until September to hold on to the money before the case comes up in court again.
But, if the money remains unclaimed the family could potentially apply for it to be returned to them under the Police Property Act.
A police spokesman said: "We have until 22 September before we have to go back to court to apply for a further order if necessary."
A spokesman for eBay said: "We know that eBay is a great place to pick up a bargain, although in this case, we agree that the contents of the parcel were somewhat unusual and we will assist with any inquiries the police may wish to make."