To clarify "Jeepster," this is technically a type of off-road Jeep (automobile) from Marc Bolan's period. So Bolan (of T.Rex fame) in their single Jeepster, is drawing a metaphor to this Jeep. The lyrics make this clear by likening the object of the Jeepsters pursuit to a "Jaguar", another popular automobile of the day.
Jaguars have remained a popular staple for enthusiasts, especially in Britain (where they're produced.) The Jeepster conversely being an American model is probably significant to Bolan's extended metaphor.
Just like a car you're pleasing to be hold
I'll call you Jaguar if I may be so bold
'Cos you're my baby, 'cos you're my love
Oh girl I'm just a jeepster for your love - oh