Is there any way I can attach my roof bars to my roof rails without purchasing another expinsive set of special clamp things?

Lash them to the rails with rope?

I would doubt it – not in any way I would be confident of being able to hold anything on there.

Have you tried Ebay? Always stuff like that for sale on there.

Is there any way we can answer the question given no information whatsoever about your kit?

what type of car/rails have you got

no more nails?

No more rails?

Why won’t your old clamps fit your rails? Or is this for a new car that has rails when you didn’t have rails previously?

That was my situation a few months ago. I bought a s/h set off eBay for £25, with bars.