Recommendations for in-car toys for a 13 mo?

[Tobermory]

Having just survived a very long,very hot and very noisy 6 hour journey home from the in-laws am now panicing slightly about our summer holidays. My 13 mo DD needs occupying ...and fast!
So what can/should i buy? Do you have any great recommendations?

I found putting together a couple of 'treasure boxes' worked well for Ds around that age - I put in things that he wouldn't normally play with and that were a bit unusual - e.g mini fluted pastry cases with loose bottoms which I happened to have - stuff he could fiddle with for a while but which was safe isywim. He loved it and going through all the contents and putting stuff in/out of the box would occupy him for a good hour at a time. Free as well