There was a time not THAT long ago (at least to me), when every pickup had a rack in the back window and if it wasn't holding guns, it held an axe handle and maybe a 4' level............
Nowadays, most folks want to keep things a little more hidden - they make one that hangs from the back of the seat and stays out of sight for the most part - depending on where you live, that might be a way to go.
Something like
this
or
this