Space Hopper
An orange rubber ball with a face and two handles.
You sat on it, gripped the horns, and bounced down the road at roughly walking pace with enormous effort.
It was genuinely exhausting and slower than walking, which nobody ever admitted. The rubber smelled extraordinary and the face was faintly sinister.
They punctured on gravel, they went soft in the cold, and every one of them eventually ended up flat behind a shed.
Cost back then
£2 19s 11d
Goes for now
£15 new; original Mettoy examples £80+