Basically as the title says, I swapped an unregistered car for another unregistered car at the time of the swap nothing was written out now I got a message from the guy saying we need a receipt, If so what for?

I'd assume it's for proof of ownership So for arguements sake he wants to get it registered he has to prove he owns that car, or maybe the cops are sus on how he got a new car, and he has to prove it's his and who he got it from

Hey mate yeah you need a receipt to get it registered just write it up on a pice of paper as you have sold the car (write type of car color Vin / eng number ect.) Then his name then say how much i wouldn't put swaps just chuck a reasonable number there Then basically his name and your name address's for both then signatures Thats how ive been doing it and have had no drama's at all

they need to know your the real owner of the car (last person who had the car in there name , so they can transfer it into there name for rego reasons. if the car wasnt in your name at all then not much point of a receipt. can be a pain in the a$$ if the cars been sold around to a few people.

The thing is you must pay stamp duty on the price of the car (or market value) so you need to show how much you paid and who you purchased it off. This also helps track stolen cars and proves ownership to some degree. It would be funny having a receipt where you traded multiple items for a car and seeing what they say when you go to register it though haha.