In the
UK, I'd say Ainsty Casting Co., and Scotia Grendel are good places to look for scatter terrain. Also, check supermarkets and toy shops for suitable toys.
I bought half a dozen of
these Tron Legacy Light Cycles, for example, and Hot Wheels motorbikes are usually about the right size. Other than that, I tend to go for 1:43 scale cars (I've got an ice cream van, Mr T's van and Doc Brown's DeLorean, myself

)