where can i get or make a cheap jeepers creepers mask from less than 70$ or £50?

This guy?

I wasn't able to find one much less than $100. A quick google search will reveal the licensed one at a few shops for $89 and up.

The best solution is a thin latex mask, but it looks like it might lend itself to simpler/cheaper processes as well. Search for "mask" right here on this site and start sifting through some of the instructables for ideas.

Take a look around for cheap halloween masks. There might be a basic one that you can modifiy with paints or added materials to look more like The Creeper.

Good luck!