Bike trailer

[Bassman]

Hey folks,
Have been offered a three bike trailer.. fitted with Indespension units, MIni wheels, Jockey wheel, and all electrics but no ramp. It is in pretty good condition , a bit of rust here and there, but built like a brick outhouse! I know nowt about trailers, so anyone got any idea what it's worth so I know if I should buy it or not? Thanks folks...
Cheers for now
Bassman