[Scorpus Flex]

I think the cheapest white kits are teamslot, although if you are looking for longevity the slot.it white kits arent too expensive compared to others, very good quality and its easier to paint. the slot.its will go better on scaley track and you can get slot.it digital chips specifically for them.

 

[Scorpus Flex]

Im not sure if they are readily available anymore but HPI skylines were super cheap for ages and came in a few different colours. You could always use the super resistant cars in different colours and add logo decals without re-painting.