I have a bbq like this http://www.popupgrill.com/ that we take camping. Over the years it has become a bit rusty and the paint has worn. Since its not getting much action due to covid, I thought I would strip the old paint, remove the rust and paint it again. I think i have found a paint called stove bright that will tolerate the high temperature and direct flame contact (lots of stove paints can't tolerate direct flame). However the faq on the paint website recommends a high temperature metal primer to stop further rusting. Unfortunately I'm really struggling to find a suitable high heat primer that doesn't cost a fortune or come from some random brand on Amazon. Has anyone done similar and could recommend some products. Thanks.
If you look at the colour chart pdf on Stove Bright's website there's a high temperature primer listed. Presumably whoever you're getting the paint from should be able to get the primer for you.
We have a black cast iron woodburner, brush it now & then with Zebo Stove Polish. There are other makes, unless Stovax is the same stuff. However, I don't know if the fact you're cooking on it makes a difference to what you need to use.
I would be looking at the cost of the paint + primer, and the cost of a new grill. Apart from paint wear, the metal can also start to thin down under the rust.
That said, the kit is so 'rustic', that i am not sure i would bother with primer. Stove paint is pretty robust on its own. If i was keeping it, id get the thick off and go over it with a couple of coats and be done with it.